diff --git a/error.go b/error.go
index e134092..99f89ec 100644
--- a/error.go
+++ b/error.go
@@ -2,6 +2,7 @@ package oops
 
 import (
 	"encoding/json"
+	"errors"
 	"fmt"
 	"log/slog"
 	"net/http"
@@ -83,7 +84,26 @@ func (o OopsError) Unwrap() error {
 // Is checks if this error matches the target error.
 // This method implements the errors.Is interface for error comparison.
 func (c OopsError) Is(err error) bool {
-	return c.err == err
+	// If the target is also an OopsError, compare their underlying errors
+	if target, ok := err.(OopsError); ok {
+		// If both have underlying errors, compare them
+		if c.err != nil && target.err != nil {
+			return errors.Is(c.err, target.err)
+		}
+		// If both have no underlying errors, compare messages
+		if c.err == nil && target.err == nil {
+			return c.msg == target.msg
+		}
+		// If one has underlying error and other doesn't, they're different
+		return false
+	}
+	
+	// For non-OopsError targets, check if our underlying error matches
+	if c.err != nil {
+		return errors.Is(c.err, err)
+	}
+	
+	return false
 }
 
 // Error returns the error message without additional context.
diff --git a/error_test.go b/error_test.go
index 81e5195..10101ca 100644
--- a/error_test.go
+++ b/error_test.go
@@ -66,3 +66,52 @@ func TestErrorsAs(t *testing.T) {
 	}, "Error: %w", assert.AnError)
 	is.True(errors.As(err, &target))
 }
+
+// TestErrorsIsWithOopsErrors tests the fix for comparing wrapped oops errors without panics
+func TestErrorsIsWithOopsErrors(t *testing.T) {
+	is := assert.New(t)
+
+	// Test case 1: Compare wrapped oops error with original oops error
+	// This was the main use case that was causing panics
+	originalErr := New("user not found")
+	wrappedErr := In("User/GetByEmail").Wrap(originalErr)
+	
+	// This should not panic and should return true
+	is.True(errors.Is(wrappedErr, originalErr))
+	
+	// Test case 2: Compare multiple levels of wrapping
+	level1Err := New("database error")
+	level2Err := In("Repository").Wrap(level1Err)
+	level3Err := In("Service").Wrap(level2Err)
+	
+	is.True(errors.Is(level3Err, level1Err))
+	is.True(errors.Is(level3Err, level2Err))
+	
+	// Test case 3: Compare with different oops errors (should return false)
+	differentErr := New("different error")
+	is.False(errors.Is(wrappedErr, differentErr))
+	
+	// Test case 4: Compare wrapped oops error with standard error
+	standardErr := errors.New("user not found")
+	wrappedStandardErr := In("User/GetByEmail").Wrap(standardErr)
+	is.True(errors.Is(wrappedStandardErr, standardErr))
+	
+	// Test case 5: Compare oops error with wrapped standard error
+	oopsErr := New("user not found")
+	wrappedStandardErr2 := In("User/GetByEmail").Wrap(standardErr)
+	is.False(errors.Is(wrappedStandardErr2, oopsErr)) // Different error types
+	
+	// Test case 6: Test with nil errors
+	is.False(errors.Is(wrappedErr, nil))
+	is.False(errors.Is(nil, originalErr))
+	
+	// Test case 7: Test with same message but different instances
+	// Note: New() creates different underlying error instances, so they shouldn't match
+	err1 := New("same message")
+	err2 := New("same message")
+	is.False(errors.Is(err1, err2)) // Different instances, should not match
+	
+	// Test case 8: Test with different messages
+	err3 := New("different message")
+	is.False(errors.Is(err1, err3))
+}
diff --git a/go.mod b/go.mod
index 651d872..45cf8b3 100644
--- a/go.mod
+++ b/go.mod
@@ -1,4 +1,4 @@
-module github.com/samber/oops
+module github.com/MathGaps/oops
 
 go 1.21
 
</div><div class="naked_ctrl">
<form action="/index.cgi/contrast" method="get" name="gate">
<p><a href="http://altstyle.alfasado.net">AltStyle</a> によって変換されたページ <a href="https://github.com/samber/oops/compare/main...MathGaps:oops:main.diff">(-&gt;オリジナル)</a>
/ <label>アドレス: <input type="text" name="naked_post_url" value="https://github.com/samber/oops/compare/main...MathGaps:oops:main.diff" size="22" /></label> <label>モード: <select name="naked_post_mode">
<option value="default">デフォルト</option>
<option value="speech">音声ブラウザ</option>
<option value="ruby">ルビ付き</option>
<option value="contrast" selected="selected">配色反転</option>
<option value="larger-text">文字拡大</option>
<option value="mobile">モバイル</option>
</select>
<input type="submit" value="表示" />
</p>
</form>
</div>