This study explores the effect of sociological and demographic factors on the intergenerational support system between adult children and their parents. More specifically it attempts to assess the impact of structural and socio-demographic factors, such as living arrangements, number of children, gender, age, and socio economic status of the adult children and their respective parents, on emotional, financial and instrumental support of the parents in Varamin, a southeastern town in Tehran province, Iran. A representative sample of 381 adult children responded to questions on various aspects of their relationship with their living elderly parents, and the kinds of supports they provide to and receive from them. Results show clear differences between mothers and fathers in their intergenerational exchange patterns. Mothers tend to give and receive more than fathers. Daughter and sons also differ in their exchanges with their parents. Sons support their parents more than daughters but when controlling for socio economic characteristics and structural opportunities of the child, the discrepancy between them tends to decrease significantly. While the flow of exchange and reciprocity persists in intergenerational exchange relationships, the scale tips increasingly in favor of elderly parents as they age or experience poorer health status.