Interrelationships among yield, some physiological factors and soil moisture were studies in Hevea. Data on girth (G), latex yield (LY), rubber yield (RY), latex solute potential ( ), rubber content (Cr), initial flow rate (F), plugging index (p), latex turgor before and after tapping (pretap and post-tap Plv), predawn leaf water potential (PD 1), and soil moisture (SM), were collected during th first year of tapping. Correlation analysis was performed to understand the relationship existing among the different variables. The contribution of different variables to yield was discerned by subjecting the correlation matrix to path coefficient analysis. By performing a series of path coefficient analyses, an explanatory model was worked out for showing the dependence of structure and path of action of factors importanta for response function. Correlation between LY and RY was close to functional. Correlations of both LY and RY with other variables were similar and the coefficients were higher for LY. The results indicated that among the system variables considered in the study, .. and Cr are the primary factors and post-tap Plv, PD .1 and G are the secondary factors influencing yield, with soil moisture as the driving force. The different variables accounted for 42 per cent of variability in yield.