In 2001, the Proceedings of National Academy of Sciences (USA) published a study on the relationship between month of birth and longevity. Subsequent studies revealed differences in month of birth among patients with acute myocardial infarction, a major killer in industrialized countries. The aim of the present study was to analyze month of birth in patients with malignant neoplasms, another major fatal disease. The study sample consisted of 44,487 patients (22,584 male) diagnosed with a malignant neoplasm at Rabin Medical Center in 1994-2011. The number of patients born in each month of the year was calculated for the whole group and by gender. Student's t-test was used to compare mean (standard deviation) monthly, quarterly and trimester values. There was a strong trend (p=0.06) for a higher mean number of births in the first trimester of the year than in the second and third trimesters. The difference was significant for male patients (p=0.03) but not female patients (p=0.13-0.15). Patients born in the first trimester of the year are more affected by malignancies, particularly males. The overall monthly birth distribution of oncology patients is in line with the paradigm linking birth month with longevity.