We report a case of systemic lupus erythematosus associated with C1q deficiency. Our patient presented at the age of 6 years with cutaneous lupus. She later developed Raynaud's phenomenon, non-scarring alopecia, oral ulceration and grand mal seizures due to cerebral vasculitis. Complement C3 and C4 levels were consistently normal during flares of her lupus and haemolytic activity of her complement was absent, suggesting a deficiency of an early component of the complement cascade. No C1q could be detected.