We investigated the feasibility of telecytology for rapid on-site evaluation (ROSE) of cytological specimens. During a six-month study, 385 consecutive adult patients underwent image-guided fine needle aspiration biopsies of the lung or transbronchial needle aspirations of mediastinal lymph nodes. Direct smears were immediately wet-fixed and a cytopathologist or a trained cytotechnologist evaluated specimen adequacy using a telecytology system. Specimens were reported as adequate or inadequate. A total of 238 specimens (62%) were diagnosed without rapid assessment. The percentage of non-representative samples in the group without rapid evaluation was 42%. In the group of 147 specimens (38%) which underwent rapid evaluation, 48 (33%) were reported as inadequate and 99 (67%) as adequate. Only 22% of final diagnoses were non-representative, including samples which were assessed as inadequate by rapid evaluation. In three patients of 32, where the obtained material was recognized as adequate, final diagnoses were non-representative. Rapid evaluation with the use of telecytology improves the diagnostic yield of guided fine-needle aspiration biopsies by decreasing the percentage of non-representative specimens.