Side-effects of angiotensin converting enzyme (ACE) inhibitors, such as a slight decrease in hematocrit, are increasingly being reported. A 14-year-old renal transplant patient on enalapril therapy developed anemia with reticulocytosis. She was investigated for other causes of anemia and enalapril therapy was ceased. Her hemoglobin level increased and reticulocyte count decreased after cessation of therapy. No other cause of anemia was found. Although anemia in patients receiving ACE inhibitors such as enalapril has previously been reported, this is the first reported patient who developed anemia associated with mild reticulocytosis and macrocytosis.