Although respiratory infections are common in pet rats, it can be challenging to differentiate infectious from neoplastic disease with imaging. The object of this retrospective study was to evaluate the diagnostic utility and outcome following ultrasound-guided pulmonary aspirates in pet rats with respiratory disease. Records from two institutions were searched to retrieve cases of rats undergoing ultrasound-guided pulmonary aspirates to work-up respiratory disease. Medical records were reviewed for information on signalment, diagnostic findings, cytology results, any ancillary diagnostics performed on aspirates, outcome, and necropsy findings. Five cases met the inclusion criteria (2006-2019). Cytologic findings included mixed eosinophilic and mastocytic inflammation (n=1), neutrophilic to eosinophilic inflammation (n=2), neutrophilic with less mononuclear inflammation (n=1), and non-diagnostic sample with only blood noted (n=1). In terms of complications, three rats had a prolonged recovery following pulmonary aspirates, one of which required hospitalization for several days in oxygen following the procedure. One additional rat arrested several hours after the aspirates, potentially related to pulmonary hemorrhage. One rat had no obvious complications reported in the medical records. Survival times following the aspirates in the other four rats were 20, 34, 85, and 569 days. Necropsy findings included bronchopneumonia (n=2) and pulmonary round cell neoplasia (n=1). In pet rats that do not respond to typical treatments for respiratory infections, diagnostics such as advanced imaging and ultrasound-guided aspirates of pulmonary masses can be considered. However, it is important to be aware of the possibility of non-diagnostic results and the risks of hemorrhage, bradycardia, desaturation, decline, and death.