Dr. Julie L. Gerberding, director of the Centers for Disease Control and Prevention (CDC) has resigned and will be replaced on an interim basis by a deputy. Dr. Gerberding, 53, the first woman to direct the agency, will leave office on Jan 20, the same day that President-elect Barack Obama is sworn into office. She was considered an effective communicator with legislators and the public and her resignation was announced in an e-mail message to employees on Friday night.

Dr. Gerberding, an infectious diseases specialist at the University of California, San Francisco, joined the disease centers in 1998 to lead a patient safety initiative and she was named director in July 2002. She also heads the Agency for Toxic Substances and Disease Registry, a sister agency to the C.D.C. and receives a total compensation of $202,200.  The two concerns have a combined budget of about $8.8 billion and more than 14,000 full-time, part-time and contract employees.

Dr. Gerberding in an e mail message to staff members in November had indicated that she would have to resign once the Bush administration left office, though colleagues said she had hoped that she would be allowed to continue.

William H. Gimson III, the Chief Operating Officer of the CDC will be the interim CDC director until the new Health and Human Service Secretary appoints someone.

An agency spokesman, Glen Nowak, said Dr. Gerberding was traveling in Africa on agency business and was not available for comment. In a statement Mr. Nowak said that the Bush administration, "as part of the transition process," had requested resignation letters from "a number of senior-level officials, including Dr. Julie Gerberding and this week, the administration accepted Dr. Gerberding's resignation, effective Jan. 20."