['Intraventricular neuroendoscopic CNS biopsiesare small, fragmented, and tissue is frequently inadequate for diagnosis. We have attempted to increase cellular yield using tumor irrigation fluid (TIF) and a cyto-histological approach for diagnosis of intracranial tumors, cysts, and infections.', 'A retrospective group of 147 cases, where only endoscopic biopsies were obtained, was compared with a prospective group of 31 cases where along with the endoscopic biopsies, tumor irrigation fluid (TIF) was collected. Tumor cyst fluid was obtained from cystic tumors (n=6). Small tumor fragments in the TIF were utilized to make squash smears (n=31). Clotted fragments were processed for sections in (n=3). Centrifuged deposit smears were prepared from tumor irrigation fluid and tumor cyst fluid.', 'Conclusive pathological diagnosis in endoscopic biopsies could be arrived at in 77.4% (24/31) prospective cases and 80.3% (118/147) in retrospective cases. Collection of TIF with a cyto-histological diagnostic approach gave a significantly higher rate of conclusive pathological diagnosis in 93.5% (29/31) cases in the prospective group.'] Does tumor irrigation fluid enhance diagnostic efficacy in endoscopic biopsies of intracranial space-occupying lesions?