This work provides a detailed characterization of cone dysmorphology and rod and cone photoreceptor loss in cpfl9 mice, which carry a novel mutant allele of Gucy2e. The mild cone-rod dystrophy disease phenotype exhibited by this mouse model may make it attractive for testing therapeutic interventions designed to mitigate the human retinal diseases caused by GUCY2D mutations. Here, GUCY2EP is linked to Rod-cone dystrophy.