Treatment with tumor necrosis factor-α inhibitors has been reported to cause weight gain in patients with psoriasis; however, limited information is available in terms of the effects of interleukin (IL)-23 and IL-17A inhibitors on bodyweight (BW) in patients with psoriasis. This study aimed to investigate the effects of infliximab, ustekinumab and secukinumab on BW and body mass index (BMI) in patients with psoriasis. We retrospectively examined changes in BW and BMI among patients treated with these biologics at our hospital. At baseline, no significant differences in BW and BMI were observed among the patients treated with infliximab (n = 18), ustekinumab (n = 30) or secukinumab (n = 20). After 7 months of the therapy, significant increases in mean BW (from 71.4 to 74.3 kg) and mean BMI (from 24.7 to 25.7) were observed in the patients treated with infliximab, whereas no significant changes were observed in those treated with ustekinumab (BW, from 70.3 to 70.1 kg; BMI, from 25.4 to 25.3) or secukinumab (BW, from 69.0 to 68.9 kg; BMI, from 25.2 to 25.2). There were no differences in the proportion of the patients who showed 75% or more improvement in the Psoriasis Area and Severity Index among the three groups. These results suggest that infliximab increases BW in the patients with psoriasis, whereas ustekinumab and secukinumab do not affect the BW in these patients.