The purpose of the study is to assess the relationship between timing of adolescent development and risk factors for suicide. Nationally representative data from the Add Health survey were used. The relationship of sociodemographic characteristics, known risk factors, and physical developmental timing and cognitive developmental style to suicide attempt was assessed. Depression was a risk factor for suicide attempts in both 9th and 11th grade. Other risk factors differed. Use of illegal drugs, homosexual orientation, using public assistance, and physical development were the important risk factors for ninth graders. For 11th graders, sexual abuse, being in counseling, and being of "other" race or ethnicity (mainly Asian or Native American) were risk factors. The cognitive development variable of using a systematic problem-solving method was protective for 11th graders. Recognizing that risk factors for adolescent suicide attempts change over time and with developmental timing of puberty is an important factor for suicide prevention strategies. (Contains 5 tables.)