Aims We sought to assess the haemodynamic profile of the Freedom stentless aortic valve compared with a stented bioprosthesis in a randomized controlled trial using echocardiography. Methods and results Sixty patients (mean age 73 years) undergoing bioprosthetic aortic valve replacement (AVR) were randomized to either Sorin Freedom stentless (n = 31) or Sorin More stented (n = 29) valves. The primary endpoints were left ventricular mass index (LVMI) reduction at 6 and 12-months. We also assessed post-operative effective orifice area index (EOAI), aortic gradient and operative time. There were no significant differences in baseline characteristics. The stentless valve was associated with a lower post-operative gradient [PG 17 (12) vs. 31 (13) mmHg, P < 0.0001] and greater EOAI [1.1 (0.3) vs. 0.8 (0.2) cm(2)/m(2), P < 0.0001]. A highly significant reduction in LVMI occurred by 6 months in both groups, but I2VMI was significantly tower in the stentless group [LVMI 119 (39) vs. 135 (30) g/m(2), P = 0.05]. However, there was continued regression of left ventricular hypertrophy (LVH) in the stented but not in the stentless group, resulting in no significant difference in LVMI at 12 months [119 (36) vs. 126 (31) g/m(2), P = 0.42]. Conclusion The use of the Sorin Freedom stentless bioprosthesis for AVR results in lower PG and greater EOA when compared with a Sorin More stented valve. This is associated with earlier regression of LVH.