The majority of market lamb produced in UK results from crossing terminal sire rams with crossbred ewes. The selection of terminal sire breeds over the past 15 years for improved carcass composition has shown positive benefits on carcass quality of their crossbred progeny (Simm et al. 2001). However, faster rates of genetic improvement would be achieved if information from these terminal sire crossbred lambs could be used in the genetic evaluation of terminal sire breeds. Incorporating crossbred information into purebred selection programmes has been modelled and the results show that it is an effective way of improving carcass quality (Jones et al. 1999). However, this is currently compromised by limitations on how individual carcass data can be collected for incorporation into breeding programmes. An innovative technology based on Video Image Analysis (VIA) of lamb carcasses is being evaluated for introduction into UK lamb abattoirs. VIA systems can provide an objective, automatic, consistent and accurate way of measuring carcass composition. However, little is known of genetic parameters for VIA measurements of lamb carcasses. Therefore the aim of the present research project was to estimate the genetic parameters of VIA carcass measurements in crossbred lamb population.