diff --git a/IssueTracker/IssueRow.cs b/IssueTracker/IssueRow.cs
new file mode 100644
index 0000000..7d4be8d
--- /dev/null
+++ b/IssueTracker/IssueRow.cs
@@ -0,0 +1,24 @@
+using CsvHelper.Configuration.Attributes;
+
+namespace IssueTracker;
+
+public class IssueRow
+{
+    [Name("Issue Type")]
+    public string IssueType { get; set; } = "";
+
+    [Name("Issue key")]
+    public string IssueKey { get; set; } = "";
+
+    [Name("Issue id")]
+    public string IssueId { get; set; } = "";
+
+    public string Summary { get; set; } = "";
+    public string Assignee { get; set; } = "";
+    public string Manager { get; set; } = "";
+    public string Status { get; set; } = "";
+    public string Created { get; set; } = "";
+    public string Updated { get; set; } = "";
+
+    public int WorkingDate { get; set; }
+}
diff --git a/IssueTracker/IssueTracker.csproj b/IssueTracker/IssueTracker.csproj
index ed9781c..cdc69f1 100644
--- a/IssueTracker/IssueTracker.csproj
+++ b/IssueTracker/IssueTracker.csproj
@@ -7,4 +7,8 @@
     <Nullable>enable</Nullable>
   </PropertyGroup>
 
+  <ItemGroup>
+    <PackageReference Include="CsvHelper" Version="33.1.0" />
+  </ItemGroup>
+
 </Project>
diff --git a/IssueTracker/Program.cs b/IssueTracker/Program.cs
index 0f07ab8..8f0b885 100644
--- a/IssueTracker/Program.cs
+++ b/IssueTracker/Program.cs
@@ -1,10 +1,165 @@
-namespace IssueTracker
+using CsvHelper;
+using CsvHelper.Configuration;
+using System.Globalization;
+
+namespace IssueTracker;
+
+internal class Program
 {
-    internal class Program
+    static int Main(string[] args)
     {
-        static void Main(string[] args)
+        if (args.Length < 2)
         {
-            Console.WriteLine("Hello, World!");
+            Console.WriteLine("Usage: IssueTracker <inputCsv> <outputCsv>");
+            return -1;
         }
+
+        var inputCsv = args[0];
+        var outputCsv = args[1];
+
+        if (!File.Exists(inputCsv))
+        {
+            Console.WriteLine($"Input CSV not found: {inputCsv}");
+            return -2;
+        }
+
+        Console.WriteLine("========================================");
+        Console.WriteLine(" Issue Tracker started");
+        Console.WriteLine($" Input : {inputCsv}");
+        Console.WriteLine($" Output: {outputCsv}");
+        Console.WriteLine("========================================");
+
+        var csvConfig = new CsvConfiguration(CultureInfo.InvariantCulture)
+        {
+            HasHeaderRecord = true,
+            IgnoreBlankLines = true,
+            BadDataFound = null, // 깨진 데이터 무시
+            MissingFieldFound = null, // 컬럼 누락 무시
+            HeaderValidated = null,  // 헤더 검증 비활성화
+            PrepareHeaderForMatch = args => args.Header.Trim()  // 헤더 공백 제거
+        };
+
+        // 1️. 최초 실행: output CSV가 없는 경우
+        if (!File.Exists(outputCsv))
+        {
+            Console.WriteLine("Tracking CSV not found. Creating new file.");
+
+            var firstIssues = LoadCsv(inputCsv, csvConfig);
+            Console.WriteLine($"[Initial] Loaded {firstIssues.Count} issues from input CSV");
+
+            SaveCsv(outputCsv, firstIssues, csvConfig);
+
+            Console.WriteLine("Tracking CSV created successfully.");
+            return 0;
+        }
+
+        // 2️. 기존 Tracking CSV 로드
+        var previousIssues = LoadCsv(outputCsv, csvConfig)
+            .ToDictionary(x => x.IssueKey);
+        Console.WriteLine($"[Previous] Loaded {previousIssues.Count} issues from tracking CSV");
+
+        // 3️. 오늘 CSV 로드
+        var todayIssues = LoadCsv(inputCsv, csvConfig)
+            .ToDictionary(x => x.IssueKey);
+        Console.WriteLine($"[Today] Loaded {todayIssues.Count} issues from input CSV");
+
+        var newIssues = new List<IssueRow>();
+        var updatedIssues = new List<IssueRow>();
+        var retainedIssues = new List<IssueRow>();
+
+        int updatedCount = 0;
+        int retainedCount = 0;
+        int newCount = 0;
+
+        // 4️. 기존 모든 이슈 처리 (입력에 없어도 유지)
+        foreach (var (key, old) in previousIssues)
+        {
+            if (todayIssues.TryGetValue(key, out var issue))
+            {
+                // 입력에 존재하는 이슈 -> 업데이트
+                if (string.Equals(old.Status, issue.Status, StringComparison.OrdinalIgnoreCase))
+                {
+                    // 상태 유지
+                    issue.WorkingDate = old.WorkingDate + 1;
+                }
+                else
+                {
+                    // 상태 변경
+                    if (string.Equals(issue.Status, "Resolved", StringComparison.OrdinalIgnoreCase))
+                    {
+                        // Resolved -> 값 유지 + 추적 중지
+                        issue.WorkingDate = old.WorkingDate;
+                    }
+                    else
+                    {
+                        // 다른 상태 변경 -> 초기화
+                        issue.WorkingDate = 0;
+                    }
+                }
+
+                updatedIssues.Add(issue);
+                updatedCount++;
+            }
+            else
+            {
+                // 입력에 없는 이슈 -> 기존 데이터 그대로 유지 (아래쪽 배치)
+                retainedIssues.Add(old);
+                retainedCount++;
+                //Console.WriteLine($"[Retained] Issue {key} not in input CSV, keeping in output");
+            }
+        }
+
+        // 5️. 입력에는 있지만 기존 추적에 없던 신규 이슈 추가 (위쪽 배치)
+        foreach (var (key, issue) in todayIssues)
+        {
+            if (!previousIssues.ContainsKey(key))
+            {
+                // 신규 Issue
+                issue.WorkingDate = 0;
+                newIssues.Add(issue);
+                newCount++;
+                Console.WriteLine($"[New] Issue {key} added to tracking");
+            }
+        }
+
+        Console.WriteLine("----------------------------------------");
+        Console.WriteLine($"Updated: {updatedCount}, Retained: {retainedCount}, New: {newCount}");
+        Console.WriteLine("----------------------------------------");
+
+        // 6️. 정렬: 신규 -> 업데이트 -> 추적 중단
+        var result = new List<IssueRow>();
+        result.AddRange(newIssues);
+        result.AddRange(updatedIssues);
+        result.AddRange(retainedIssues);
+
+        Console.WriteLine($"Total output rows: {result.Count}");
+        Console.WriteLine("----------------------------------------");
+
+        // 7️. 결과 저장
+        SaveCsv(outputCsv, result, csvConfig);
+
+        Console.WriteLine("Tracking CSV updated successfully.");
+        return 0;
+    }
+
+    private static List<IssueRow> LoadCsv(string path, CsvConfiguration config)
+    {
+        using var reader = new StreamReader(path);
+        using var csv = new CsvReader(reader, config);
+
+        return csv.GetRecords<IssueRow>().ToList();
+    }
+
+    private static void SaveCsv(
+        string path,
+        List<IssueRow> data,
+        CsvConfiguration config)
+    {
+        using var writer = new StreamWriter(path, false, System.Text.Encoding.UTF8);
+        using var csv = new CsvWriter(writer, config);
+
+        csv.WriteHeader<IssueRow>();
+        csv.NextRecord();
+        csv.WriteRecords(data);
     }
 }