In the present study, the fiber type specificity of dihydropyridine (DHP) and ryanodine (Ry) receptors in different rat limb muscles was investigated. Western blot and histochemical analyses provided for the first time evidence that the expression of both receptors correlates to a specific fiber-type metabolism. We observed a significant (p = 0.01) correlation between DHP as well as Ry receptor density and the expression of MHC IIa (Pearson's correlation factor r = 0.674 and r = 0.645, respectively) in one slow-twitch, postural muscle (m. soleus), one mixed, fast-twitch muscle (m. gastrocnemius) and two fast-twitch muscles (m. rectus femoris, m. extensor digitorum longus). The highest DHP and Ry receptor density was found in white part of m. rectus femoris (0.058 ± 0.0060 ODu and 0.057 ± 0.0158 ODu, respectively). As expected, the highest relative percentage of MHC IIa was also found in the white part of m. rectus femoris (70.0 ± 7.77%). Furthermore, histochemical experiments revealed that the IIA fibers stained most strongly for the fluorophore-conjugated receptor blockers. Our data clearly suggest that the expression of DHP and Ry receptors follows a fiber type-specific pattern, indicating an important role for these proteins in the maintenance of an effective Ca²⁺ cycle in the fast contracting fiber type IIA.