102 rheumatoid arthritis (RA) and 104 psoriatic arthritis (PsA) patients' records were analysed according to a standardised protocol. Using Cox regression, life-table analysis and log rank test, the effectiveness and toxicity of, and duration of disease modifying antirheumatic drug (DMARD) treatment were compared in RA and PsA. RA patients were treated with gold sodium thiomalate (GST), methotrexate (MTX) and sulphasalazine (SSZ) for a median duration of 35, 72 and 12 months respectively, whereas PsA patients were treated for 12, 12 and 17 months. The differences for GST and MTX were statistically significant (p=0.0043 and 0.0447). Drug toxicity was more frequently seen among patients with PsA (p=0.0023). No difference in efficacy could be proved. Results suggest that there is a significant difference between RA and PsA patients in terms of toxicity of these agents. Therefore, separate treatment strategies are needed, and earlier results with RA may not be directly applicable to PsA.