The increase in cardiovascular risk in patients with rheumatoid arthritis (RA) compared with the general population is due to the combined effect of traditional risk factors for cardiovascular diseases, metabolic disorders, systemic inflammation, and side effects of antirheumatic drugs. Tofacitinib (TOFA) is an oral reversible inhibitor of janus kinases for the treatment of RA with proven efficacy and good tolerability, but its effects on body weight and metabolic profile need to be clarified. We investigated the effects of TOFA on body mass index (BMI) and visceral adiposity index (VAI) in RA patients. Thirty-one consecutive patients with active RA and starting new treatment with TOFA were included in a prospective 1 year follow-up observational study of cardiovascular effects of TOFA treatment. Weight, height, waist circumference, BMI, blood pressure, lipid profile, fasting glucose and VAI were measured at baseline and 12 months of treatment. Median weight gain was 3 kg (4.2%) after 1 year of TOFA. 23 (74%) patients suffered from a weight gain, and 6 (26%) out of them from a weight increment of 10% or more. Patients with lower BMI (p = 0.024) and higher baseline DAS28 [ESR] (p = 0.017) have the risk of an increase in BMI > 5% during TOFA treatment in a multivariate analysis. A decrease in VAI after 12 months was recorded. Weight increment and improvement of VAI are frequent on TOFA treatment. BMI dynamics associated with higher disease activity at baseline and lower baseline BMI.