Purpose : The objective of this study was to describe the sonographic features of deep-seated lipomas. ; Methods : A retrospective review of the sonographic features of 64 deep seated lipomas in 64 patients (43 females, 21 males, mean age 46.5, range 16–77 years) seen over an 8-year period (1998–2006) was undertaken. ; Results : Features evaluated were location, size, shape, marginal definition, internal echogenicity, including the presence of intermingled muscle fibres and linear internal echoes, acoustic transmission and vascularity. Confirmation was histological in 37 (58%) cases and by typical magnetic resonance imaging (MRI) appearance in 27 (42%) cases. ; Conclusion : The results show that although the features of deep-seated lipoma are more variable than those reported for subcutaneous lipomas, the presence of thin internal echoes in conjunction with other less specific features should enable a correct diagnosis.