We report risk factors associated with intraocular penetration of caterpillar hair seen at our institute from January 2005 to December 2007. Records of all patients with caterpillar hair induced ophthalmitis (CHIO) were retrospectively reviewed for clinical characteristics, anatomic location of lodgment of the caterpillar hair, treatment methods, and outcomes. Out of a total of 544 cases of CHIO, 19 eyes (seven in the anterior chamber and 12 in the posterior segment) experienced intraocular penetration (3.5%). The presence of deep intracorneal hair (80 cases, 14.7%) was found to be the only risk factor for intraocular penetration ( P < 0.001). The removal of intracorneal hair was possible in only 29 out of 80 eyes (36%) and this was associated with a significantly reduced risk of intraocular penetration ( P = 0.022). Patients with retained intracorneal hairs should be counseled regarding risk of intraocular penetration and closely followed up for at least six months.