Thermal analysis can be utilized to reveal the total graphite nucleated in cast irons by correlating the integrated areas under the cooling curves and graphite areas of a cast iron sample measured using an image analyzer. The aim of this study is to determine the effect of varying amounts of inoculants on the thermal analysis of grey cast iron by observing the changes in the shape of the cooling curves. DeltaT values, i.e. the observed undercooling before recalescence, can be correlated to the changes in the microstructure and mechanical properties which is a consequence of inoculation. In this study, a series of gray cast iron alloys produced by a cast iron foundry were used as test alloys and 'thermal analysis' was performed using a "multilab thermal analyzer" device to record and analyze the cooling curves. Afterwards, the areas under the cooling curves, particularly the portion belonging to graphite formation, were integrated after curve fitting of these segments. The areas were plotted against the total graphite areas measured by the image analyzer. Casting trials and thermal analysis were undertaken at a local foundry which produces automotive parts.