<b>Introduction:</b> Linear endobronchial ultrasound (EBUS) is a highly effective for the diagnosis of mediastinal tumours. In routine clinical practice, it is common to send samples from both fine-needle aspiration (FNA) biopsy as well as bronchial washing (BW) for cytologic testing, though the diagnostic yield of the latter has not been evaluated. <b>Objective:</b> To assess the diagnostic accuracy of cytologic testing of BW as a complement to EBUS-FNA. <b>Material and Methods:</b> We performed a cross-sectional diagnostic accuracy study in 164 patients referred for Linear EBUS-FNA. We calculated the accuracy statistics including the area under the ROC curve, overall diagnostic accuracy and diagnostic yield. Two-tailed P values <0.05 were considered statistically significant. <b>Results:</b> EBUS-FNA were performed in stations 7 (51.5%) and 4R (33.9%), and 9.1% were mediastinal masses. The EBUS-FNA was diagnostic in 89.7% of cases. BW Cytology had a diagnostic yield of 2.4%, all BW cytologies matched the results of EBUS-FNA and provided no additional information for diagnosis. BW cytology sensitivity was 2.8% and specificity 100%. The area under the ROC curve was 0.51 (IC95%: 0,44 a 0,59; P=0.86)). The overall diagnostic accuracy was 0.15. The diagnostic OR was 1.33 ((IC95%: 0,07 a 26,3; P = 0,62). <b>Conclusion:</b> Cytologic assessment of BW during Linear EBUS-FNA showed poor diagnostic yield and accuracy and provided no additional diagnostic value to EBUS-FNA
