Maternal effect genes produce mRNA or proteins that accumulate in the egg during oogenesis and control the developmental program until embryonic genome activation takes place. NLRP5 (NLR family, Pyrin domain containing 5), also called MATER (Maternal Antigen That Embryos Require) is one of the genes required for normal early embryonic development, although its precise function remains to be elucidated. The aim of the present study was to analyze the NLRP5 gene expression pattern and protein distribution in somatic tissues and germ cells in the pig. Reverse transcription was performed on mRNA from germinal vescicle (GV) oocytes and total RNA from spermatozoa and tissues from different organs. The transcript for NLRP5 gene was identified only in ovaries and oocytes. The presence of NLRP5 protein was detected only in ovaries by western blot analysis and immunohistochemistry.