Mediterranean mussel is the main farming bivalve species in the area of Boka Kotorska Bay. In this paper results about biometric parameters of cultivated Mediterranean mussel in the area of Boka Kotorska Bay are present. Research was performed on two farms in Orahovac and Kamenari since January 2015 up to January 2016. Biometric parameters indicate morphological plasticity, but further and detailed analysis as morphological ratios are required. Condition index (CI) was calculated according to three different methods. All three methods gave similar results and indicate on spatial and temporal CI variation. The lowest CI was during September, while the highest was during February/March. Very strong and strong correlation between all three methods are obtained. Methods based on wet meat weight are reliable for temporal and spatial CI interpretation in mussels.