Aim: Sarcoplasmic reticulum (SR) Ca²⁺ ATPases (SERCA) play a central role in Ca²⁺ homeostasis and contractile function in skeletal muscle. We hypothesized that skeletal muscle-specific loss of SERCA2 would affect slow-twitch muscle relaxation by slower removal of Ca²⁺ from the cytosol and reduced force generation due to reduced Ca²⁺ transient size. Methods: Serca2^flox/flox MLC-1f^wt/cre (MLC1f-SERCA2KO) micewere obtained by mating Serca2^flox/flox mice with MLC-1f^wt/cr mice. Serca2^flox/flox animals were used as controls. Gene alleles were detected by PCR. Quantification of mRNA and proteins was performed by real-time qRT-PCR and immunoblotting. Contractile measurements were performed on in situ muscles. Results: Serca2 gene excision was detected in soleus, extensor digitorum longus, tibialis anterior, gastrocnemius muscles and the diaphragma, but not in the heart or in nonmuscle tissue. MLC1f-SERCA2KO mice appeared overall normal. In soleus muscle, Serca2 mRNA and SERCA2 protein were reduced to 6 ± 2 % (SEM) and 6 ± 2 % of control values, respectively. The expression of Serca1 and Serca3 mRNAs and proteins were not changed. The mRNA levels of other Ca²⁺ transporting proteins or myofilament protein components were unaltered. Preliminary in situ experiments showed that there was no difference between MLC1f-SERCA2KO and control soleus muscles in the maximum tetanic force generation and relaxation rates. Conclusions: Our preliminary conclusions are that MLC1f-SERCA2KO soleus muscle show normal contractile properties in spite of near loss of SERCA2.