Objectives: This study was conducted to evaluate the frequency and pattern of haematological abnormalities (HA) in SLE patients at the time of diagnosis and last follow-up, and their relationship with organ involvement. Patients and methods: This retrospective study included patients who were diagnosed and treated for SLE from 1982 to 2008 at King Khalid University hospital, Riyadh. Demographic and haematological parameters at diagnosis and the last follow-up, disease manifestations, organ involvement and clinical haematological complications were recorded. Association of HA with organ involvement was explored by multivariate analysis. Results: A total of 624 patients (90.7% females, mean age 34.3 +/- 11.9 years) were studied. HA were present in 516 (82.7 %) patients at the time of diagnosis. Anaemia was the most frequent HA in 63.0% patients followed by lymphopenia in 40.3%, leukopenia in 30.0%, thrombocytopenia in 10.9% and autoimmune haemolytic anaemia (AIHA) in 4.6% patients. Deep vein thrombosis and pulmonary embolism were diagnosed in 7.4% and 2.6% patients respectively. After a mean follow-up of 9.3 +/- 5.3 years, 329/491 (67%) patients still had some HA present. Anaemia remained the most common abnormality (51.7% patients) followed by lymphopenia in 33.1%, and thrombocytopenia in 4.8% patients. Leukopenia was associated with oral ulcers (p=0.021) and alopecia (p=0.031), anaemia with renal disease (p=0.017), AIHA with neurological involvement (p=0.003), elevated IgG with malar rash (p=0.027), and low C3 with serositis (p=0.026). Conclusion: HA are very common at the time of diagnosis and during follow-up in SLE, and some of these abnormalities are associated with organ damage. This information may help in better management planning of SLE patients.