Knowledge of the nitrogen nutrition status of the vine is essential for long-term management of its nutrition with the aim of producing high-quality grapes. Measurement of the chlorophyll index is a fast, non-destructive and relatively inexpensive method that provides a good approximation of the nitrogen nutrition status of the vine during the growing season. Several chlorophyll meters are available on the market, each using its own measurement unit. With the aim of popularizing the use of chlorophyll meters, the interpretation thresholds of the SPAD index, measured on the vine at the veraison stage, have been established from correlation with the N-tester index, for which the thresholds are already known.