This is a cross sectional study to find the prevalence of adolescent depression, suicidal ideation and associated socio-demographic factors among adolescent students. 3141 students aged between 15 to 19 years from residential and non-residential government and private schools and colleges from Davangere participated in the study. The self administered questionnaire of Beck's depression inventory II was used to evaluate the depression status and suicidal ideation was analyzed using item number 9 of BDI. The prevalence of depression in our study group was 57.7%. The prevalence of suicidal ideation was significantly (P =0.000 ) more among depressed (41.7% ) compared to non-depressed (11.4%). Residential school students were more depressed (74.5%) than non-residential school students (52.1% , P = 0.000 ). Students from joint family were less depressed (40.1%) compared to those from nuclear family (63.3%, P =0.000). Moderate depression was the commonest type followed by mild, severe and extreme types. Age, sex, class, recent academic performance, mother's education level, factors at home like quarrel, financial, alcoholism and chronic illness in parents showed significant relationship with prevalence of depression. Depressed students had problem getting along with parents, siblings, friends and teachers. Parents education level and occupation status had no association with depression rates. To conclude the prevalence of depression in adolescent students of our study group was high and suicidal ideation was significantly high among the depressed students.