The aim of the present study was to evaluate the performance of the Finnish diabetes risk score (FINDRISC) for identifying undiagnosed type 2 diabetes in a German population and to develop a more simplified alternative model. We invited 921 individuals with a family history of the metabolic syndrome in a cross-sectional survey. Of these, 771 subjects completed the FINDRISC questionnaire and underwent an oral glucose tolerance test. The performance of the FINDRISC was assessed using the area under the receiver operating characteristics curve (ROC-AUC). The ROC-AUC of the FINDRISC was 0.81 (0.76-0.87). We detected no difference in diabetes prevalence between individuals with or without a family history of diabetes. Two logistic regression models (continuous- and categorical-model) were developed using the diagnosis of diabetes as the dependent variable, and age, body mass index (BMI), waist circumference, use of blood pressure medication, and history of high blood glucose as independent variables. After stepwise backward elimination of the insignificant variables, the following variables remained: age, BMI, and history of high blood glucose. The ROC-AUCs for the continuous- and categorical-models were 0.88 (0.85-0.92) and 0.86 (0.82-0.90), respectively, and were significantly larger than the ROC-AUC of the FINDRISC. There was no significant difference between the ROC-AUC of fasting plasma glucose and those of the two regression models. The FINDRISC questionnaire can be used to identify undetected diabetes in a German population. The simplified version, the categorical-model, may be a useful alternative for identifying asymptomatic type 2 diabetes.