The relationship between the body weight of the Philippine native horse and its external body measurements such as height, hearth girth, midriff girth, flank girth, and body length was determined. Possible equations for body weight estimation were constructed based on the said parameters. One hundred thirty three (133) female and 33 male apparently healthy Philippine native horses with age ranging from 4 months to 25 years old were used in the study. Regression analysis showed that a linear relationship exists between body weight and external body measurements. For the whole sample population, heart girth was found to be the best single predictor of weight. When combinations of parameters were used for predicting weight of the sample population, heart girth, midriff girth, body length 1 and height were found to be the best predictor of weight. Statistical analysis using t-test showed that a non-significant difference (P>O.05) exists between the actual weights and the estimated weights obtained using the derived formulae. Therefore, these formulae could be used to fairly estimate body weight in the absence of a suitable weighing scale.