INTRODUCTION There are nearly no studies about the association between Baker's cyst (BC) and medial meniscal tear (MMT) using ultrasonography. PATIENTS AND METHODS Nonselected patients who were referred for ultrasonography for the evaluation of knee pain were recruited. Demographic, clinical, and ultrasound parameters were documented. RESULTS One-hundred and nineteen patients were included and 131 knees were evaluated. There were 59 (~50%) female patients and mean age of 46.4±17.7 years. BC was found in 31 knees (23%). BC was significantly associated with MMT (P=.029) and age (P=.002) after adjusting for other covariates. CONCLUSIONS BC was strongly associated with MMT regardless of other intraarticular abnormalities.