The incidence of drumsticks and of sessile nodules as well as the lobe counts of the neutrophil nuclei have been studied in three patients with XXX and three patients with XXXY chromosomes. Three patients with XXY Kline-felter’s syndrome, six apparently normal women and one male were used as controls. The patients with chromosomal abnormalities had on an average a lower incidence of drumsticks and a lower mean lobe count than the controls with normal chromosomes. The incidence of sessile nodules appeared to be increased in the patients with XXX and XXXY chromosomes, but not in those with XXY Klinefelter’s syndrome. It is suggested that in patients with three X chromosomes, the additional X, although unable to form more drumsticks owing to an inhibition of nuclear segmentation, may express itself in a higher incidence of sessile nodules. It is further suggested that an inhibition of segmentation of the neutrophil nuclei associated with a lowering in the number of drumsticks may be a common feature in patients with chromosomal abnormalities.