By screening for mutations that perturb the invagination of the vulva of the Caenorhabditis elegans hermaphrodite, we have isolated 25 mutations that define eight genes. We have named these genes sqv-1 to sqv-8 (squashed vulva). All 25 mutations cause the same vulval defect, an apparent partial collapse of the vulval invagination and an elongation of the central vulval cells. Most sqv mutations also cause an oocyte or somatic gonad defect that results in hermaphrodite sterility, and some sqv mutations cause maternal-effect lethality. We propose that the sqv genes affect a pathway common to vulval invagination, oocyte development, and embryogenesis.