“I work too hard.”
“I’m a perfectionist.”
“I am workaholic.”

But that’s not what interviewers want to hear. They want you to tell your real weakness. They are smart enough to see the trick. So, a good answer is to tell your true weakness.

IT is a huge field; most IT pros could be strong on certain areas but weak on others. What you can do is to pick up an area which is a non-key element of the position as a weakness. If it is a DBA job, you may say your weakness is lack of project management experience. If you are applying for a programmer job, your weakness could be less experience on network administration. Just pick a neutral weakness about something that’s not critical to the job, then you should be fine.

After telling your weakness, explain what you’ve done to overcome the weakness, which shows that you are actively seeking ways to improve yourself. Through this approach, you present yourself as a reasonable, honest person who recognizes areas that need to grow.

The following answer is for a Java programmer position:

“Although I have extensive experience in Java programming, I am relatively weak in network administration. Couple of times in my previous job I had to get help from the network team to setup networked QA test environment. I wish I could do it by myself, so I’ve spent spare time to grab some hands-on network skills. I’ll continue building experience in network area as network skills become more important to programmers in today’s enterprise computing environment.”