Enrofloxacin is commonly used to treat bacterial infections in psittacine birds. Enrofloxacin is most effective if dosed per os or by injection, but can be delivered via medicated drinking water. The purpose of this project was to measure the plasma concentrations of enrofloxacin achieved by offering drinking water medicated with an injectable enrofloxacin formulation at 200 mg/L to 16 psittacine birds for 10 days. The birds included 6 cockatoos (Cacatua species), 4 conures (Aratinga species), 2 Senegal parrots (Poicephalus senegalus), 2 red-shouldered macaws (Ara nobilis), and 2 grey parrots (Psittacus erithacus). The injectable formulation was selected because it is readily available in most veterinary hospitals. Blood samples for plasma enrofloxacin and ciprofloxacin assay were collected at 1600–1730 hours on treatment days 2 and 4 and 0830–1000 hours on days 6 and 8. Mean plasma enrofloxacin concentrations (± SD) ranged from 0.11 ± 0.05 to 2.00 ± 1.43 μg/ml for each bird and were 0.40 μg/ml or less for 14 of 16 birds. Ciprofloxacin concentrations were below the limits of detection for all but 2 samples. This study shows that water medicated with the injectable formulation of enrofloxacin at 200 mg/L maintains plasma concentrations in psittacine birds that are adequate only for treating systemic infections caused by highly susceptible bacteria.