Objectives To determine the prevalence and associated factors of unrecognized depression among patients who visit non-psychiatric outpatient departments in the University of Gondar specialized teaching hospital. North West Ethiopia. Methods An institution-based cross-sectional study was conducted among Medical outpatient departments in the University of Gondar specialized referral hospital from March to April 2019. We collected data through face-to-face interviews. We recruited 314 participants for face-to-face interviews using the systematic random sampling technique. The patient health questionnaire (PHQ-9) was used to measure depression. Coded variables were entered into Epi Info version 7 and exported to SPSS version 20 for analysis. Descriptive statistics and multivariable logistic regression analysis were used. Adjusted odds ratios (AOR) with a 95% confidence interval were used to calculate significance. Results A total of 314 participants were interviewed with a response rate of 100%. The prevalence of depression was 15.9% with (95% CI (12.1–20.1)). In the multivariate logistic regression revealed that, able to read and write (AOR = 0.24, 95% CI (0.67–0.84)), secondary education (AOR = 0.34, 95% CI (0.12–0.91)), education in college and university level (AOR = 0.32, 95% CI (0.13–0.78)), poor social support (AOR = 7.78, 95% CI (2.74–22.09)), current cigarette smokers(AOR = 12.65, 95% CI (1.79–89.14)) were associated with depression. Conclusion The prevalence of depression among outpatient attendees was high. We recommend an early depression screening be carried out by health professionals.