The principle of "cost effectiveness" has been used by economists for many years to determine the most suitable enterprise to introduce under a given production system. Simple benefit-cost analysis has been used to determine the most cost effective enterprise or optimum intercrop combination. Benefit- cost ratios are determined for each enterprise or intercrop combination and the one with the highest ratio is selected. The aim of this paper is to examine some simple benefit-cost analysi s techniques which farmers could use to determine optimum intercrop combination under coconut based farming systems.