IT professionals must dress to impress to land a job in 2009, because CIOs say they consider a formal business suit the most appropriate attire for a job interview, the results of a recent survey show.

Forget the fact that most IT professionals don casual wear in the office -- CIOs want to see job candidates put an effort into their appearance when interviewing at their companies. According to a poll of 1,400 CIOs by Robert Half Technology, 35% of CIOs expect interviewees to wear a formal business suit. Another 26% want to see khakis and a collared shirt on potential employees; and -- not to leave the ladies out -- 24% expect female IT professionals to put on a skirt and blouse or tailored separates, such as a jacket and dress pants.

Jeans and a polo shirt seemed acceptable attire for just 9% of those polled by the IT staffing and consulting firm.

"Employers want to see that job candidates have made an effort to dress appropriately for the work environment," said Katherine Spencer Lee, executive director of Robert Half, in a statement.

Job seekers should dress professionally but remember to stay comfortable and make sure the outfit they choose is free from stains and wrinkles, Robert Half says. Things to avoid during an interview: distracting clothing, big jewelry, and excessive perfume, cologne or makeup. The firm also advises job seekers to ask a recruiter or someone working at the company about the best attire for that environment.

"While a suit isn't the best choice for every interview, it's better to err on the side of overdressing vs. appearing too casual," Lee said.