Summary: Increasing environmental concerns from intensive dairy production systems surrounding nitrogen loses has stimulated research and development on mitigation and monitoring technologies focusing on urination behavior of dairy cows. The Lincoln University PEETER V1.0 sensor is a promising piece of technology for monitoring cow urination behavior. The objective of this study was to validate the use of the PEETER V1.0 sensor in vivo. Fifteen lactating Holstein-Friesian × Jersey dairy cows were fitted with the PEETER V1.0 sensor and housed within metabolism crates for 72 h. Every urination event during this period was collected manually and compared with the PEETER V1.0 sensor estimations of each event. The PEETER V1.0 sensor was found to have both excellent precision and accuracy for estimating urination events and is therefore a promising piece of new technology for monitoring animal urination behavior.