A combination of poor oral hygiene and dry mouth may be hazardous to the oral health status. However, systematic assessments in order to detect oral health problems are seldom performed in the nursing care of the elderly. The aims of this study were to investigate the occurrence of oral health problems measured using the Revised Oral Assessment Guide (ROAG) and to analyse associations between oral health problems and age, gender, living conditions, cohabitation, reason for admission, number of drugs, and functional and nutritional status. One registered nurse performed oral health assessments using ROAG in 161 newly admitted elderly patients in rehabilitation care. Oral health problems were found in 71% of the patients. Thirty per cent of these patients had between four and eight problems. Low saliva flow and problems related to lips were the most frequent oral health problems. Problems in oral health status were significantly associated with presence of respiratory diseases (problems with gums, lips, alterations on the tongue and mucous membranes), living in special accommodation (low saliva flow, problems with teeth/dentures and alterations on the tongue), being undernourished (alterations on the tongue and low saliva flow) and being a woman (low saliva flow). The highest Odds ratio (OR) was found in problems with gums in relation with prevalence of respiratory diseases (OR 8.9; confidence interval (CI) 2.8-27.8; P < 0.0005). This study indicates the importance of standardised oral health assessments in order to detect oral health problems which can otherwise be hidden when the patients are admitted to the hospital ward.