Psoralen + ultraviolet A (PUVA) therapy is an established modality for psoriasis. As India is a tropical country that has good availability of natural sunlight psoralen + sunlight (PUVAsol) may be a more convenient option. To compare the efficacy and cost-effectiveness of PUVA versus PUVAsol in chronic plaque psoriasis. Cases of chronic plaque psoriasis with body surface area ≥10% or Psoriasis Area and Severity Index (PASI) ≥10, excluding erythrodermic or pustular psoriasis, were randomized to receive either PUVA or PUVAsol, with endpoint being the achievement of PASI 90 or completion of 12 weeks treatment, whichever is earlier. Cost analysis was also undertaken. Thirty-six cases (16 in PUVA and 20 in PUVAsol group) completed treatment. In the PUVA group, 15 cases (93.75%) responded to therapy while in the PUVAsol group, 15 (75%) responded (P = 0.29). Mean baseline PASI in the PUVA and PUVAsol groups was 16 and 14.4, respectively, and at endpoint was 1.62 and 3.77. There was a significantly greater reduction in PASI in the PUVA group at 2 and 4 weeks but at 8 and 12 weeks and endpoint, it was comparable. Treatment failure occurred in 6.25% and 25% of cases respectively (P = 0.29). Side effects were higher with PUVA. Total cost of therapy was significantly higher in the PUVA group (P = 0.002). Cost-effectiveness ratio was US$0.72 with PUVA and US$0.37 with PUVAsol. Both PUVA and PUVAsol were equally efficacious, with PUVAsol being twice as cost effective. Hence, PUVAsol may be recommended as treatment for psoriasis in a developing economy such as India.