diff --git a/src/main/java/edu/unc/lib/boxc/migration/cdm/services/SourceFileService.java b/src/main/java/edu/unc/lib/boxc/migration/cdm/services/SourceFileService.java
index 89c0d24d..9200c5cb 100644
--- a/src/main/java/edu/unc/lib/boxc/migration/cdm/services/SourceFileService.java
+++ b/src/main/java/edu/unc/lib/boxc/migration/cdm/services/SourceFileService.java
@@ -20,6 +20,7 @@
 import org.slf4j.Logger;
 
 import java.io.BufferedWriter;
+import java.io.File;
 import java.io.IOException;
 import java.io.Reader;
 import java.nio.file.FileSystems;
@@ -222,13 +223,14 @@ private Map<String, List<String>> gatherCandidatePaths(GenerateSourceFileMapping
         Files.walkFileTree(basePath, new SimpleFileVisitor<Path>() {
             @Override
             public FileVisitResult visitFile(Path path, BasicFileAttributes attrs) throws IOException {
-                if (pathPattern == null || pathMatcher.matches(path)) {
+                var relativePath = basePath.relativize(path);
+                if (pathPattern == null || pathMatcher.matches(relativePath)) {
                     String filename = path.getFileName().toString();
                     if (options.isLowercaseTemplate()) {
                         filename = filename.toLowerCase();
                     }
                     List<String> paths = candidatePaths.computeIfAbsent(filename, f -> new ArrayList<>());
-                    paths.add(basePath.relativize(path).toString());
+                    paths.add(relativePath.toString());
                 }
                 return FileVisitResult.CONTINUE;
             }
diff --git a/src/test/java/edu/unc/lib/boxc/migration/cdm/services/SourceFileServiceTest.java b/src/test/java/edu/unc/lib/boxc/migration/cdm/services/SourceFileServiceTest.java
index 61cf8f1d..b03b4d88 100644
--- a/src/test/java/edu/unc/lib/boxc/migration/cdm/services/SourceFileServiceTest.java
+++ b/src/test/java/edu/unc/lib/boxc/migration/cdm/services/SourceFileServiceTest.java
@@ -190,6 +190,26 @@ public void generateNestedMatchesTest() throws Exception {
         assertMappedDatePresent();
     }
 
+    @Test
+    public void generateBasePathMatchesTest() throws Exception {
+        testHelper.indexExportData("mini_gilmer");
+        GenerateSourceFileMappingOptions options = makeDefaultOptions();
+        // test source files are in the source subdirectory of the base path
+        options.setPathPattern("source/*.tif");
+        // add nested path
+        testHelper.addSourceFile("nested/path/276_182_E.tif");
+        Path basePath = testHelper.addSourceFile("276_183_E.tif");
+
+        service.generateMapping(options);
+
+        SourceFilesInfo info = service.loadMappings();
+        assertMappingPresent(info, "25", "276_182_E.tif", null);
+        assertMappingPresent(info, "26", "276_183_E.tif", basePath);
+        assertMappingPresent(info, "27", "276_203_E.tif", null);
+
+        assertMappedDatePresent();
+    }
+
     @Test
     public void generateTransformedNestedMatchTest() throws Exception {
         testHelper.indexExportData("mini_gilmer");
@@ -822,11 +842,6 @@ private void assertExceptionContains(String expected, Exception e) {
                 "Expected message exception to contain '" + expected + "', but was: " + e.getMessage());
     }
 
-    private void setIndexedDate() throws Exception {
-        project.getProjectProperties().setIndexedDate(Instant.now());
-        ProjectPropertiesSerialization.write(project);
-    }
-
     private void assertMappedDatePresent() throws Exception {
         MigrationProjectProperties props = ProjectPropertiesSerialization.read(project.getProjectPropertiesPath());
         assertNotNull(props.getSourceFilesUpdatedDate());