Ball indentation technique (BIT) is employed to study the effect of post-weld heat treatment on the mechanical properties of a high strength low alloy (HSLA) steel and subsequently on the quality of the weldment. Well-defined load-deflection curves and corresponding true stress-strain curves for different zones (base, HAZ, weld) of sectioned sample (top and middle) and their validation with mechanical properties obtained by conventional method established the effectiveness of the present ball indentation (BI) set up. Investigations on microstructure of all the zones have been carried out to find out a correlation with the obtained mechanical properties. Evaluation of the mechanical properties of materials through BIT could characterize the heat-affected zone in weld HSLA steel.