Autologous rich plasma (PRP) is blood plasma with enhanced concentration of platelets and is enriched with several growth factors which stimulate tissue regeneration. The current study aimed to investigate the effect of PRP on hair regrowth in patients with alopecia areata (AA) totalis. Ten subjects (28.9 ± 6.28 years; five males and five females) with clinically diagnosed AA totalis for at least 3 years who had not received any treatment within 3 months prior to the study were recruited. Blood sample was collected in thrombocyte harvesting tubes. The PRP was separated via centrifugation. The patients' scalp was divided sagittally into two approximately equal parts. In each patient, 4 mL of PRP was injected intradermally into the left or right side of the scalp; in each point, 0.1 mL of PRP was injected. Each patient was followed up monthly for 4 months. No hair regrowth was seen in eight patients and in two patients only <10% hair regrowth was observed. Totally, no significant effect was found for PRP on hair regrowth (p > .05). There was no side effect during treatment. Single dermal PRP injection did not prove to have any effect on hair regrowth in these patients.