Body weight is one of the most important traits which has quantitative traits inheritance. QTL mapping not only provides useful information regarding the status and number of genes controlling quantitative traits. It can also help the breeders in marker-assisted selection. This study aimed to identify QTL affecting body weight on chromosomes 1 and 5 in Markhoz goats using microsatellite markers. The studied population consisted of 248 animals from 8 half sib families genotyped for eleven microsatellites on chromosomes 1 and 5. Phenotypic data including body weight at birth, 4 months, 6 months, 9 months and 12 months of age that were corrected for fixed effects including year of birth, sex and type of birth. QTL analysis was performed based on regression analysis. In this research significant QTL was not found on chromosome 1 while one chromosomal regions associated with weight at 4 and 6 months of age was found on chromosome 5. The location of the detected QTL was 2 to 8 cM near the OarFCB005 marker. Maybe this region of chromosome 5 contain genes that affect growth trait. Considering that the locations of this QTL was near the location of OarFCB005 marker, if further investigation were performed, this marker could be used in marker-assisted selection.