diff --git a/flares.py b/flares.py
index d308f25..9a365fa 100644
--- a/flares.py
+++ b/flares.py
@@ -310,21 +310,39 @@ script_dir = os.path.dirname(os.path.abspath(__file__))
 os.chdir(script_dir)
 
 
-# Configure logging to file with timestamps and realtime flush
+# Configure logging with rotation to prevent indefinite growth
+# Issue #114: Log file should not grow indefinitely - now rotates at 10MB, keeps 5 backups
+import logging.handlers
+
 if PLATFORM_NAME == 'darwin':
     log_path = os.path.abspath(os.path.join(os.path.dirname(sys.executable), "../../../fnirs_analysis.log"))
 else:
     log_path = os.path.join(get_app_dir(), "fnirs_analysis.log")
 
-logging.basicConfig(
-    filename=log_path,
-    level=logging.INFO,
-    format='%(asctime)s - %(processName)s - %(levelname)s - %(message)s',
-    datefmt='%Y-%m-%d %H:%M:%S',
-    filemode='a'
+# Create logger
+logger = logging.getLogger()
+logger.setLevel(logging.INFO)
+
+# Clear any existing handlers
+logger.handlers.clear()
+
+# Create rotating file handler (max 10MB per file, keep 5 backups = ~50MB max total)
+rotating_handler = logging.handlers.RotatingFileHandler(
+    log_path,
+    maxBytes=10*1024*1024,  # 10 MB
+    backupCount=5,          # Keep 5 backup files
+    encoding='utf-8'
 )
 
-logger = logging.getLogger()
+# Set formatter
+formatter = logging.Formatter(
+    '%(asctime)s - %(processName)s - %(levelname)s - %(message)s',
+    datefmt='%Y-%m-%d %H:%M:%S'
+)
+rotating_handler.setFormatter(formatter)
+
+# Add handler to logger
+logger.addHandler(rotating_handler)
 
 
 def set_config_me(config: dict[str, Any]) -> None: