Diagnostic ultrasound imaging systems typically employ the traditional delay and sum (DAS) beamforming for image reconstruction because of its reduced complexity. But the limited contrast and resolution of DAS beamformed images makes it difficult for the detection of small lesions with a single non-steered plane wave insonification. To address these limitations, this paper demonstrates a novel beamforming technique named as beam multiply and sum (BMAS) for enhancement of contrast and lesion detectability with a non-steered plane wave insonification. The intensity linearity of BMAS is evaluated in-silico and the contrast is evaluated in-vitro and in-vivo. When compared to DAS, BMAS images for in-vitro datasets showed an improvement of 33%, 16.78% and 6.3% in lateral resolution, contrast ratio and contrast-to-noise ratio, respectively.