The Instrumentation and Sensing Laboratory (ISL) has developed a multi-spectral imaging system for on-line inspection of poultry carcasses. The ISL design is based on two principles: (1) wholesome and unwholesome birds have different chemical compositions of tissues and may have different skin color, and (2) unwholesome carcasses may have physical abnormalities which can be detected by computerized imaging. On-line trials of the multi-spectral chicken carcass inspection system were conducted during a 14-day period in a poultry-processing plant in New Holland. Pennsylvania, where spectral images of 13, 132 wholesome and 1459 unwholesome chicken carcasses were measured. For off-line model development, the accuracies for classification of wholesome and unwholesome carcasses were 95% and 88%. On-line testing of the neural network classification models with combination of the filter information was performed, The inspection system gave accuracies of 94% and 87% for wholesome and unwholesome carcasses, respectively. This accuracy was consistent with the results obtained previously on laboratory studies. Thus, the inspection system shows promise for separation of unwholesome chicken carcasses from wholesome carcasses in poultry processing lines. Published by Elsevier Science Ltd.