In an ultrastructural study of the hepatopancreas of <i>Porcellio scaber, </i>an obligate intracellular parasite, <i>Chlamydia, </i>was noted in the epithelial cells. Although the infection was found to extend the entire length of the hepatopancreas, it was most extensive in the glandular region. Indirect immunofluorescence testing revealed no cross-reactivity with either lymphogranuloma venereum or psittacosis antisera.