This research focused on the comparative study between the length of growing season, millet (Pennisetum americanum L.) and sorghum (Sorghum bicolor (L) moench) yields in Kano State, Nigeria in the period spanning from 1981 to 2010. The data for the investigation are daily rainfall records, millet and sorghum yields sourced from Nigerian Meteorological Agency (NiMet) at Aminu Kano International Airport and Kano State Agricultural and Rural Development Authority (KNARDA) respectively. The study attempted to identify the level of length of growing season, millet and sorghum yields in ton/ha, examine the trend of length of growing season, millet and sorghum yields and compare their trends. Data collected analyzed using decriptive statistics and least square regression model. Descriptive statistics was used to compute cumulative pentad rainfall and an ogive of cumulative rainfall pentad. Using Pentad and Julian day calendars, an annual ogive of cumulative pentad was drawn using Microsoft Excel and determined length of growing season in the study period. Least square regression model was used to determine linear trend line and trend directions of length of growing season, millet and sorghum yields. Results obtained indicate that as the trend of length of growing season increases, the trends of millet and sorghum yieds decreases. Based on these results, it recommended that agricultural stakeholders should encourange farmers toward intensive agriculture rather than extensive by providing adequate agricultural inputs at subsidize price.