This study concerned evaluating of body mass index (BMI) as a nutritional status characteristic and trying to detect its influence on milk or meat production in original Wallachian sheep. Multivariate analysis of these relationships was performed by principal component analysis. GLM procedure was used to determine linear regressions between BMI and nutritional status characteristic or ewe productivity traits. BMI had a positive association with all the body energy reserves characteristic. The strongest orientation was demonstrated between BMI and musculus longissimus lumborum et thoracis depth, when 1 point increase of BMI was associated with 1.27 mm (P < 0.01) increase of muscle depth. Contrary, the lowest relation of BMI was noticed with body condition score (P > 0.05). BMI also showed to have the higher influence on the milk (P < 0.05), and meat (P > 0.05) productivity traits than all the nutritional status attributes. BMI is a complex attribute including a body weight as well as body dimension. Its positive association with others nutritional status traits indicated its use as additional attribute. The relations of BMI with the productivity traits showed it as an interesting tool in flock management.