More than 90% of cases of pneumocystis pneumonia (PCP) in adults occur in patients with chronic HIV infection with CD4 counts lower than 200 cells/ml. Even though primary HIV infection can cause transient profound CD4 lymphocytopenia, PCP is rarely reported during primary HIV infection. We report a case of a 26-year-old man who was diagnosed with PCP in the setting of primary HIV infection. He was successfully treated with a 21-day course of oral co-trimoxazole.