Background: To report 2 cases of large subretinal haemorrhage in 2 patients with age-related macular degeneration when the intravitreal injections were changed from bevacizumab (Avastin) to ranibizumab (Lucentis). Methods: Both patients were treated initially with intravitreal bevacizumab 1.25 mg for 4 months (4 injections) and then switched to 0.5 mg ranibizumab which continued for another 6 months. Best-corrected visual acuity measurements, slit-lamp examination, contact lens biomicroscopy, optical coherence tomography and fluorescein angiography were performed at baseline examination and every month. Results: Both patients showed initial improvement when treated with intravitreal bevacizumab followed by deterioration and development of a large subretinal haemorrhage when changing to intravitreal ranibizumab. Conclusions: There is not enough experience switching from one anti-vascular-endothelial-growth-factor agent to another. A prospective study with large series of patients and controls may be necessary in order to determine whether it is safe enough to change from one medication to another.