A dense cataract prevents detailed fundus examination which may lead to delayed diagnosis of undiscovered intraocular pathology before cataract surgery. We report two cases where large choroidal melanomas were diagnosed after cataract surgery and/or Nd:Yag laser capsulotomy. In the first case, a dense cataract prevented proper examination of the fundus of an 84-year-old female. A brownish choroidal lesion was seen after cataract surgery and diagnosed as postoperative choroidal detachment. As this lesion persisted over months, the patient was sent to our hospital for evaluation where a diagnosis of choroidal melanoma with extrascleral growth was made and an enucleation with implantation of a dermis-fat graft was performed without complication 10 days later. In the second case, a 58-year-old female patient had Nd:Yag laser treatment 2 years after cataract surgery had been performed. During fundus examination 1 day after treatment, the ophthalmologist noticed a choroidal lesion which he suspected to be a reaction to the laser treatment and referred the patient to our hospital where a diagnosis of a mushroom-shaped choroidal melanoma with serous retinal detachment was made. These cases show that preoperative evaluation of the posterior segment prior to cataract surgery or other therapeutic interventions is essential in order to identify any pathology. In case of a dense cataract, additional imaging such as ultrasound sonography is recommended in order to exclude intraocular lesions and to visualize the optic disc in suspected glaucoma.