Introduction: Neonatal jaundice is characterised by a yellow coloration of the skin, mucous membranes, and sclera of the eye resulting from the accumulation of bilirubin in the body. When produced in significant excess, bilirubin can accumulate in the central nervous system causing kernicterus (bilirubin encephalopathy). The diagnosis of jaundice based only on the visual assessment of the degree of yellowing of the skin or sclera and the urine output is not a reliable method. Even the assessment by experienced observers does not correlate with actual measurements of serum bilirubin levels. Therefore, a study was undertaken to determine whether other parameters could clarify the diagnosis of neonatal jaundice during the observation of an infant. The aim of this study was to analyse the effect of bilirubin levels on motor activity of the infants studied in terms of the quality of motor patterns assessed using the Prechtl method. Materials and methods: The research procedure was multistage and included a retrospective analysis of neonatal medical records, transcutaneous measurement of bilirubin levels, and analysis of neonatal activity performed based on video recordings. A qualitative assessment of neonatal spontaneous activity was performed using the Prechtl GMA method (general movement assessment). The research procedure consisted of two stages. The first stage involved selecting infants who had a good general health status. Based on these criteria, a total of 125 infants were included in the video recording. The second stage of study inclusion took place after video recording. Infants with short periods of wakefulness, prolonged crying, and lying on their side were excluded from further examinations. Ultimately, 52 infants were included in the study. All infants were subjected to the diagnostic method proposed by Prechtl to determine the effect of bilirubin levels on their motor activity. Conclusion: Bilirubin levels in the course of physiological jaundice did not affect the quality of motor repertoire in the group of infants studied. Therefore further research is needed.