Disease activity may be questioned as a possible related factor to depression in patients with rheumatoid arthritis (RA) and Behcet disease (BD). Our aims were to determine and compare the depression levels of patients with RA and BD and to investigate a possible association between disease activity and depression scores of the patients. A total of 30 RA and 30 BD patients were included in this study. In RA patients; pain, morning stiffness duration, systemic involvement, tender-swollen joints, the physician-patient global assessments and DAS28 scores were determined. In patients with BD, the BD Current Activity Form was assessed for disease activity. Beck depression inventory (BDI) was used for the evaluation of patient groups. BDI score above 13 was considered as cut-off point for depression. Pearson's correlation and Mann-Whitney U tests were used for statistical analysis. In RA patients, in spite of no correlation between disease activity and depression, a significant correlation between BDI scores and pain was determined (p < 0.000; r = 0.615). In BD group; positive correlations between BDI scores and patient's impression of disease activity and arthralgia were determined (p < 0.014 and p < 0.001, respectively). Number of BD patients with higher BDI scores than cut-off point was significantly more than those in RA group (p < 0.039). Pain in RA patients, and patient's impression of disease activity and joint involvement in BD patients were found as related factors to the depression scores. The greater ratio of BD patients with higher depression score than those in RA indicates the need for increased awareness of depressive symptoms in patients with BD.