Introduction Patients with rheumatoid arthritis (RA) often experience depression, which has a very negative impact on the assessment of the quality of life (QoL). However, there are not many studies that assess the relationship between depression and QoL in RA patients. The aim of the study was to assess the level of QoL and determine the mutual relationship between anxiety and depression levels and QoL in patients treated for RA. Material and Methods The study included 101 patients (aged:52.4±16.97), who met the established criteria for a diagnosis of RA and treatment with a biological agent. Only standardized tools were used to examine the patients: WHO-QoL, HADS and the VAS scale. Results The mean RA duration in the group studied was 13.54±9.51 years and the disease activity score was 4.8±0.8. The mean QoL perception score was 3.48± 0.8. Nearly 40% of the respondents could not clearly determine their QoL, perceiving it as neither poor nor good, and 10% believed their QoL is poor or very poor. The correlation analysis revealed that anxiety is significantly and negatively associated with QoL in the psychological domain (r = −0.472, p < 0.001) and social domain (r = −0.298, p = 0.023) and depression is significantly and negatively associated with QoL in the psychological domain (r = −0.322, p = 0.01) and physical health domain (r = −0.209, p = 0.04). In the multiple linear regression model, depression was an independent negative predictor affecting the following domains: perception of QoL and perception of health, and physical health. Conclusion RA patients treated with biologics present a low level of health perception and an average level of QoL perception. Depression and anxiety negatively correlate with QoL domains: the higher the anxiety and depression levels, the poorer the QoL in the psychological and social relationships domains. Depression is an independent determinant of decreased QoL.