Abstract: Background: In Kenya the number of Human Immunodeficiency Virus (HIV) infected people eligible for initiation of antiretroviral Therapy (ART) is increasing. The national ART comprehensive care Clinic programmatic success requires that patients who are taking ART remain on treatment and are followed up regularly to ensure they adhere to treatment protocol and to reduce cases of drug resistance and arising toxicities. This study investigated factors associated with being lost to follow-up, in a cohort of patients enrolled in HIV comprehensive care clinic at Kipiripiri of Nyandarua county.