In the last years there is ,an increasing technological interest in light emitting diodes and lasers in the blue and green regions of the spectrum, with an important emphasis on the ZnSe-based diodes [1]. ZnSe is one of the most interesting II-VI wide-bandgap materials, but it is known that one of the problems of ZnSe electronic devices is related with device degradation. Lately, BeTe chalcogenide has been proposed as an alternative material for performing II-VI photonics. In this contribution we will present a theoretical study of the nearly matched ZnSe/BeTe (100) heterojunctions. We perform our study with first principles total energy calculations in the framework of the density functional theory within the local density approximation, LDA. We focus our interest on the possibility of band offset control with the composition of the interface region [2]. We analyse the effect of the interface composition (ZnTe or BeSe-like interfaces), and the effect of the interface strain in the valence band offset. Our results show clearly the importance of the strain contribution and the effect of the interface chemical composition, providing interesting information for the use of these altenative materials in II-VI based heterojunctions.