Sudden Unexpected Infant Death (SUID), including Sudden Infant Death Syndrome (SIDS), causes the fatality of 3,700 babies in the United States each year. While there is no definite cause of SIDS, possible baby’s physiological indicators (BPIs) of an onset of SIDS include changes in temperature, heart rate, and respiration rate. The team aimed to design a device to increase a baby’s safety and well-being during sleep by emitting an auditory and visual alert when the BPIs fall outside of a healthy range. Currently available consumer devices do not monitor the BPIs and therefore cannot offer a safety level comparable to this device. This project incorporates the entire monitoring system into a baby’s onesie in order to monitor the BPIs without introducing additional objects to the crib environment. The system uses an algorithm programmed into a minicomputer to analyze the BPI recordings obtained through the specific sensors. The alert system is used to warn the baby’s parent or caregiver of a potential onset to SUID and is comprised of a buzzer and LED. All electrical components are fluid resistant and can be removed to allow the onesie to be machine washable. Verification testing proved that each sensor recorded values accurately with 95% confidence. Testing confirmed that the device can alert parents or caregivers when values fall out of their respective physiological range. Overall, the final design met the proposed requirements and specifications, making it suitable for use in monitoring a baby’s heart rate, respiration rate, and temperature during sleep.