The aims were to study the gender differences in clinical manifestations, disease course and organ damage in systemic lupus erythematosus (SLE). Clinical manifestations, autoantibody profile, relapses and damage scores were obtained from 51 Chinese males with SLE and compared with 201 consecutive female SLE controls. Fifty-one males were identified among 630 SLE patients who attended our clinics, giving a male prevalence of 8% and a female to male ratio of 11.4-1. Both the male SLE patients and the female controls had similar age and SLEDAI score at disease onset. Male SLE patients had less alopecia (P = 0.03), Raynaud's phenomenon (P = 0.01) and anti-Ro (P = 0.049) during the course of the disease but none of the differences were statistically significant after correction for multiple observations. The prevalence of major organ involvement in either sex was not different. Both groups of patients had a comparable mean duration of follow-up (104 vs. 102 months, P = 0.87). Males had a significantly lower rate of relapses (total No. of flares/patient-year: 0.23 in men vs. 0.33 in women, P = 0.04), but the frequency of severe flares (No. of severe flares/patient-year in men 0.08 vs. 0.12 in women, P = 0.16) was not significantly different from the females. Male patients with positive anti-Ro had significantly less overall flares than their female counterparts who were anti-Ro positive (0.16 vs. 0.34, P = 0.006). However, the use of immunosuppressive agents for disease control in patients of both sexes was similar. 22 (43%) of the males and 78 (39%) of the females had organ damage. A higher percentage of male patients had impairment of renal function (P = 0.006) but the proportion of patients who required dialysis was not different (4% in men vs. 2% in females. P = 0.92). There was also a trend of more cardiovascular damage in the males but the difference was not statistically significant (P = 0.09). The mean SLICC/ACR scores were not significantly higher in the males than the females (0.71 vs. 0.60, P = 0.47). Males tend to differ from females in clinical manifestations, immunological profile and disease course in SLE. However, there was no gender difference in the involvement of major organs/systems. Males had less overall disease flares than the females but the rate of severe flares was not significantly lower. For patients who were anti-Ro positive, males had significantly less total number of flares/patient-year than their female counterparts. More renal impairment and cardiovascular damage was present in our male lupus patients but the overall damage scores were not significantly higher.