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Moisture content (Psi) of poultry manure or litter is an important property of the material. Relating manure or litter Psi to its ammonia (NH3) emission is conducive to assessing and/or controlling real-time ammonia emissions from the manure or litter. However; means to measure manure or litter on a real-time basis is lacking. This study was carried out to characterize the operational performance of a commercially available soil moisture sensor for measuring V of meat-bird (broiler and turkey) litters and laying-hen manure. The Psi tested ranged from 27.1% to 65.7% for broiler litter, 22.8% to 56.1% for turkey litter, and 11.0% to 75.0% for layer manure. Bulk density (rho) ranged from 318 to 468 kg m(-3) (20 to 29 lb ft(-3)) for the broiler and turkey litters and from 151 to 943 kg m(-3)(9 to 55 lb ft(-3)) for laying-hen manure. Linear regression equations were developed to relate the sensor output to Psi and rho for the meat-bird litters and to Psi for the laying-hen manure, all yielding good fit (R-2=0.95 -0.99). An uncertainty analysis performed on the developed calibration equations revealed average errors in the V estimation of +/- 7.1% estimated value for the poultry litters and +/- 6.7% estimated value for the laying-hen manure. Litter temperature was found to have a small impact on Psi measurement by the sensor, 0.31% of measured mV per degrees C (0.17% per degrees F) deviation from the mean operating temperature over the range of 4 degrees C to 24 degrees C (39 degrees F to 75 degrees F). Results of the study indicate that when properly calibrated, the soil moisture sensor offers a reasonable means for real-time measurement of poultry litter or manure moisture content.