diff --git a/minio/thread_pool.py b/minio/thread_pool.py
index 52ee5668a..45e18ff41 100644
--- a/minio/thread_pool.py
+++ b/minio/thread_pool.py
@@ -26,12 +26,13 @@
 
 """
 
-import sys
 from threading import Thread
 from .compat import queue
 
+
 class Worker(Thread):
     """ Thread executing tasks from a given tasks queue """
+
     def __init__(self, tasks_queue, results_queue, exceptions_queue):
         Thread.__init__(self)
         self.tasks_queue = tasks_queue
@@ -42,7 +43,7 @@ def __init__(self, tasks_queue, results_queue, exceptions_queue):
 
     def run(self):
         fast_quit = False
-        while True:
+        while not self.tasks_queue.empty():
             func, args, kargs = self.tasks_queue.get()
             if not fast_quit:
                 try:
@@ -57,12 +58,12 @@ def run(self):
 
 class ThreadPool:
     """ Pool of threads consuming tasks from a queue """
+
     def __init__(self, num_threads):
         self.results_queue = queue()
         self.exceptions_queue = queue()
-        self.tasks_queue = queue(num_threads)
-        for _ in range(num_threads):
-            Worker(self.tasks_queue, self.results_queue, self.exceptions_queue)
+        self.tasks_queue = queue()
+        self.num_threads = num_threads
 
     def add_task(self, func, *args, **kargs):
         """ Add a task to the queue """
@@ -72,6 +73,10 @@ def parallel_run(self, func, args_list):
         """ Add a list of tasks to the queue """
         for args in args_list:
             self.add_task(func, args)
+
+        for _ in range(self.num_threads):
+            Worker(self.tasks_queue, self.results_queue, self.exceptions_queue)
+
         # Wait for completion of all the tasks in the queue
         self.tasks_queue.join()
         # Check if one of the thread raised an exception, if yes