Recently, thiazolidinediones have shown to be efficacious with a favorable safety profile when used in the treatment of chronic plaque-type psoriasis. The aim of this study was to evaluate and compare the efficacy and safety of a combination of methotrexate plus pioglitazone and methotrexate alone in plaque-type psoriasis. A total of 44 adult patients with plaque-type psoriasis were included in the study. Patients were randomized to treatment with methotrexate alone (group A) or methotrexate plus pioglitazone (group B) for 16 weeks. The primary efficacy outcome measure was psoriasis area and severity index (PASI) score change between the study groups at week 16 relative to baseline. The secondary efficacy outcome measure was dermatology life quality index (DLQI) score change between the two groups at week 16 relative to baseline. The PASI 75 score was also measured. After 16 weeks of therapy, the percentage of reduction in the mean PASI score was 70.3% in group B and 60.2% in group A. PASI 75 was achieved in 14 patients (63.6%) in group B compared with two patients (9.1%) in group A within 16 weeks, which was significant (P < 0.001). At 16 weeks from the baseline, a 63.6% decrease in the mean DLQI score of group B was seen, while the decrease for group A was 56.9%. Pioglitazone enhances the therapeutic effect of methotrexate in plaque-type psoriasis, as demonstrated by a reduction in the mean PASI scores. In terms of DLQI, there was no extra benefit by the addition of pioglitazone to methotrexate therapy.