Abstract: The investigation to see the effect of different phosphorus levels viz., 0, 50, 75, 100 and 125 kg P2O5 ha‾1 with a recommended constant dose of nitrogen @ 150 kg ha‾1 on the leaf growth of two maize varieties was carried out. The experiment was laid out in Randomized Complete Block Design (factorial) with four replications. The maize cultivars included were Composite-17 against a standard variety Akbar. Leaf extension rate (LER) was calculated as the slope of a linear regression fitted to the points along the A-B position of the graph. Final leaf length (FLL) was measured as lamina plus sheath when the individual leaf was fully expanded. Using data for final leaf length and the calculated LER, the duration of leaf extension rate (LED) was calculated. Standard procedures were adopted to record the yield component parameters. The values of linear correlation (r) were worked out to get a relationship between FLL, LER with other growth and yield parameters influencing grain yield in maize. FLL and LER were positively correlated with phosphorus applications. Similarly number of grains per cob, grain weight per cob, 1000-grain weight and grain yield were also significantly correlated with FLL and LER. Therefore, the later two parameters were directly responsible for increasing the various yield components in maize.