This article is resulted from a sociological investigation about social pathology of the adolescents in the one - parental families. The sample was 200 girls and 200 boys from families in which father was dead and the mother had the obligation to administer the whole aspects of the family. The study was conducted in Tehran city (in 17 zones). The purpose of the study was to examine the rate of social pathology of the adolescents in these families and effects of lack of father on tendency of adolescents to deviation. Methods were documentary and survey. The technique of the data collection was standardized questionnaire, in this research probability of existence of significant correlation between lack of father and theft, traffic of drugs, suicide, flight from home, premature sexual relation with the persons of other sex, use drugs, smoking was tested. The result indicated that, rate of traffic of drugs and premature sexual relations with persons of other sex is zero and other variables have significant correlation with the lack of father. The highest rate of deviation is decision to suicide and the lowest rate is related to the theft.the most variable is capacity of the family to meet material needs of adolescents, which is itself influenced from the lack of father. The rate of control carried out by mother is also a very significant variable. This variable has significant correlation with social pathology among adolescents. Whenever the health of the family is in danger, the health of the society is also in danger. We suggested, thus, some guidelines that is necessary for the state, family, school, religious institutions and adolescents themselves, to apply.