Farm animal welfare is a societal concern, and the need exists for scientific protocols to assess welfare. This paper describes the development of a protocol to assess the welfare of sheep (Ovis aries) and its application in 36 farms in Norway. There were two parts to the protocol; the animal- and resource-based measurements obtained during farm visits, and the analysis of production data. Data collection took place during visits to 36 farms in the lambing season (April-May) in 2007 (n = 11) and 2008 (n = 25). A fear test was conducted, and ewes were scored on a scale from 0 to 3. Forty-one percent of the ewes tested had a fear score of 3, indicating the lowest level of fear. Mean (± SD) fear score across farms were 1.9 (± 0.5). Higher fearfulness was found to be associated with lower ewe body condition scores (BCS). Mean (± SD) BCS across farms was 2.6 (± 0.6). A relatively large proportion of the ewes had a BCS of 2 (41%), which may be associated with an increased risk of nutritional stress, disease and low productivity. Eight farms had more than 5% (range 5.4-24.4%) of lamb carcases categorised in the lowest conformation class, which may be an indication of a welfare problem. This study is the first step in the development and validation of a welfare assessment protocol for sheep, and further research is needed to assess the overall reliability of the protocol.