The need to determine adequate nitrogen (N) levels for potato crops in Southeast Idaho during the growing season has required expensive petiole sample tests. The use of a SPAD Minolta chlorophyll meter by potato producers could reduce sampling costs and provide accurate in-season potato petiole N levels. The objective of this study is to compare the SPAD chlorophyll meter and petiole samples for accuracy in measuring N petiole levels for in-season N fertilization for potato crops.  Nitrogen treatments of 0, 56, 112, 168, 224, and 280 N kg ha^-1 with three to four replications in a randomized complete block design were used to establish different N levels in the potato crop. Fertilizer was split applied with 56 kg N ha^-1 applied at planting and remainder applied in June and July.  Petiole nitrate (NO₃^-) samples, chlorophyll meter readings, and soil NO₃^- test were taken weekly for 8 wks beginning in July through mid August.  Chlorophyll meter readings were compared to petiole NO₃^- and soil NO₃^- levels, which are current methods for determining in-season N fertilization need.  Potato plots were harvested by digging 3 meters of two adjacent rows and yields were determined based on total weight and weight by quality class.  Yield data were compared with petiole NO₃^-, chlorophyll meter data, and soil NO₃^- levels for determining which method best predicts yield.   Correlation between SPAD meter and petiole showed that in order to meet the early season 20,000 mg kg^-1 petiole NO₃^- threshold the chlorophyll meter reading must meet or exceed 47. For mid season, the petiole NO₃^- threshold drops to 15,000 mg kg^-1 and the correlating chlorophyll reading is 41.  Similarly when the late season petiole NO₃^- threshold drops to 10,000 mg kg-¹ the chlorophyll reading remains 41.  The similar chlorophyll meter reading between the mid and late season petiole NO₃^- levels is due to the lack of new vegetative growth and a lower NO₃^- concentration need in the petioles. Yield data did not correlate to N application, petiole chlorophyll meter readings probably due to large spatial variance and a large amount of residual N.  Our data supports that chlorophyll meter readings accurately indicate N responsiveness of the crop 80-100% of the time when compared to petiole samples. Additional data will be needed to refine and support chlorophyll meter readings as a method to base in-season N fertilization decisions in potatoes.