Ten female and seventy two male patients suffering from ankylosing spondylitis were studied to evaluate differences between the two sexes. Low lumbar backache and inactivity stiffness were the commonest presenting complaints in females (8/10) as compared to males (34/72). They also had a later age of onset (25.4 + 6.16 yrs) compared to males (20.56 + 6.57 yrs). Females were found to be symptomatically milder with a more benign course of the disease. There were no significant differences in the frequency of extra-articular features and HLA B27 between males and females. A positive family history was more often seen in female ankylosing spondylitis (50%) than male (31.94%) patients.