Hajj is a unique Islamic ritual where around 2.5 million Muslims gather annually in the Kingdom of Saudi Arabia. The objective of this work was to determine epidemiological pattern of diseases and risk behaviors of pilgrim patients during Hajj 1427 H. A cross sectional study was conducted at two randomly chosen Mina hospitals and a total of 248 patients were selected using systematic random sample method. Results show that about two-fifths (39.1%) of patients had chronic diseases and only 34.4 % received health education before Hajj. The commonest patients' complaints were cough, dyspnea and fever (28.2 %, 27.4% and 25 % respectively). Acute respiratory infections and gastrointestinal illnesses were the commonest diagnosed diseases. Analgesics and antibiotics were the most commonly prescribed drugs. Regarding risky behaviors, 24.6 % of pilgrims were unvaccinated against meningococcal meningitis, 87.9 % didn't wear protective masks and 43.1 % had their hair shaved or cut by re-used razors or scissors. Pilgrims who followed organized camps and who received health education before hajj conducted significantly lower risky behaviors compared to others.