Our aim was to study the usefulness of jaundice visual assessment combined with skin bilirubin determination in 517 healthy newborns. Yellowness assessment was made and babies were included in three different bilirubin classes. Skin bilirubin and total serum bilirubin were determined within 10 minutes from the visual assessment. This latter led to underestimation of serum bilirubin in 16.7-40.4% and overestimation in 4.9-35.7% of newborns. Skin bilirubin measurement after the visual assessment decreased the risk of underestimation to 0-9.2% and the risk of overestimation to 2.1-11.1%. The majority of visual assessment errors were performed in the more lighted hours of the morning (75%), while the smallest number (39%) occurred during the afternoon. Skin bilirubin measurement significantly corrected these diagnostic errors (p < 0.001, p < 0.02) without differences during the day. Clinical estimate is unreliable for evaluating the need for serum bilirubin assay. Using the addition of skin bilirubin determination is a more advisable approach.