The objective of the study was to determine the chemical composition of eight heifer muscles and the changes in solubility of intramuscular collagen, texture profile, and shear force at the 2^nd and 14^th day of their post-slaughter ageing. The investigations were carried out on the following muscles: pectoralis profundus (PP), infraspinatus (IS), triceps brachii (TB), serratus ventralis (SV), biceps femoris (BF), semimembranosus (SM), semitendinosus (ST), and longissimus dorsi (thoracis et lumborum) (LD) of the well fleshed heifers of the lowland black-white breed. The chemical determinations of raw and grilled muscles were performed according to the relevant Polish Standards, and the solubility of collagen according to the modified method of Liu et.al. [1994]. The Texture Profile Analysis (TPA) and shear force measurements of grilled muscles were conducted using a TA-XT2 texture analyzer. The beef muscles under analysis varied in their basic chemical composition and in their collagen content. Among the raw muscles, LD contained the highest amount, and SM and BF the lowest amount of soluble collagen, whereas among the grilled muscles: IS and TB respectively.14 days after the slaughter ageing, the collagen solubility in raw and grilled muscles increased by ca. 5.5 % on average compared to the samples analyzed 2 days after the ageing. The ST and SM muscles were characterized by the highest TPA hardness and TPA chewiness values, whereas the SV, IS and LD by the the lowest. The shear force values were the highest in SM, and the lowest in IS. Irrespective of the muscle type, the values of the parameters: TPA hardnes, chewiness, and shear force values decreased 14 days after the post-slaughter ageing by about 17N, 6N, and 20N, respectively.