To determine the effect of intraperitoneal and intravitreal D-penicillamine (DPA) on retinal neovascularization in a murine model of oxygen-induced retinopathy.On postnatal day 7, 16 mice were injected intraperitoneally with 300 mg/kg/day DPA for 3 days followed by 50 mg/kg/day for 7 days. A different group of 7 mice were injected intraperitoneally with 600 mg/kg/day DPA for 3 days followed by 100 mg/kg/day for 7 days. A third group of 14 mice were injected with 1,500 mg/kg/day DPA for 2 days; a control cohort of 17 mice received intraperitoneal phosphate-buffered saline (PBS). An additional 15 mice underwent intravitreal injection of 1 μL of 100 mg/mL DPA in the right eye and 1 μL PBS intravitreally in the left eye as a control. All groups were placed in a 75% oxygen chamber for 7 days then room air for 3 days before being sacrificed and enucleated. The retinas were stained and flat-mounted to determine the severity of retinal neovascularization by quantifying neovascular buds.After intraperitoneal injection, the mean number of glomeruli and tubules was similar in the DPA and PBS groups (P = 1.0), regardless of DPA dosage. The dosage of 1,500 mg/kg/day proved to be uniformly lethal. After intravitreal injections, the mean number of glomeruli (P = 0.16) and tubules (P = 0.7) were similar in the DPA and PBS groups.Neither intraperitoneal nor intravitreal injection of DPA inhibits retinal neovascularization in a murine model of oxygen-induced retinopathy.