It is essential that producers know the nitrogen status of their cotton crop throughout the growing season. Laboratory tests often do not provide accurate and rapid assessment of crop N status. A chlorophyll meter may be able to provide rapid and accurate determination of N status of cotton plants. Field studies that provided a wide range of N sufficiency were used to: (1) evaluate a chlorophyll meter (SPAD 502, Minolta Camera, Ltd. Japan) for consistency and accuracy of determining N levels in cotton plant leaf blades, (2) determine if the chlorophyll meter could be used to monitor treatment effects on N availability and uptake by cotton plants, and (3) determine the effect of variety and leaf age on chlorophyll readings. SPAD chlorophyll readings were strongly associated with N availability (R² = 0.8 – 0.99), whether from fertilizer or legume N. The meter was able to identity small differences in N availability as affected by tillage practices or termination date of cover crops. Leaf age and variety had large effects on SPAD readings. The SPAD chlorophyll meter was an accurate instrument for determining N status of cotton in uniform experiments and may have applications in commercial production fields. Because of inherent difference among varieties in leaf color, the meter will require calibration for each variety and, perhaps, other factors.