Purpose: To report the clinicopathological features of corneal buttons in patients with congenital primary aphakia. Methods: Five corneal specimens of five patients with congenital primary aphakia who underwent penetrating keratoplasty (PKP) were studied by light microscopy, and immunohistochemistry with anti-smooth muscle (SMA) antibody. Results: All patients were born from consanguineous parents. Of the five, two patients were identical twins. All eyes were microphthalmic. In four patients, congenital primary aphakia was bilateral and in one patient (Patient 3), it was unilateral. PKP failed in all eyes due to hypotony. Histologically, Bowman's layer was absent in all specimens. The corneal stroma was thin; however, the stromal collagen showed thick and irregularly arranged fibers with neovascularization in all eyes. Descemet's membrane and the corneal endothelium were absent in all specimens. In three specimens, atrophic iris tissue without dilator muscle was adherent to the posterior corneal surface. In addition, anteriorly displaced hypoplastic ciliary body and/or pigmented and non-pigmented ciliary epithelium were attached to the posterior corneal surface in three of the five specimens. SMA staining demonstrated disorganized ciliary muscle in one case. SMA-positive stromal keratocytes demonstrated their myofibroblast nature. Conclusion: The corneal findings in congenital primary aphakia are similar to that seen in other causes of congenital corneal opacification. The anteriorly displaced hypoplastic ciliary body that was partially excised during keratoplasty explains the ocular hypotony in these eyes.