Indigenous poultry breeds are of a major importance to supply the rural population with eggs and meat in many developing countries of the world (Esmaelkhanian et al., 2004). A successful animal breeding plan is a continuous process of elimination and searching in a way that breeder could be able to manipulate genetic variation for changing a population to optimise desired phenotypes (Williams et al., 2002). As highlighted by Chambers (1990) animal’s body weight, which could be easily measured, is probably the most frequently used indicator of growth at a specific age. In practical animal breeding programmes, the breeding objective is usually genetic improvement of production and reproduction traits for a population under consideration. Knowledge of genetic parameters is of crucial importance to be implemented for predicting breeding value of candidate animals. The main objective of this study was to estimate heritability of body weight at week 8 for Iranian indigenous chickens through Bayesian statistical approach using an animal model.