The aim of this investigation is to develop functional food recipes that combines millets and edible seaweed (Ulva fasciata), to help maintain blood sugar levels in diabetes mellitus patients. The U. fasciata sample was procured from Kanniyakumari, Tamil Nadu, and botanically authenticated at CSMCRI, Rameswaram. The U. fasciata thallus was subjected for Drosophila melanogaster toxicity studies, to assess the effect on mortality, fecundity, negative geotaxis and feeding behaviors for both acute and chronic durations. It was concluded that the procured U. fasciata sample is non-toxic and it improves the physiological functioning of the flies such as neural, muscular, digestive function and feeding potential of the flies. Further, the seaweed was infused into three unique functional food recipes i.e., Ragi Soup, Sorghum Ice Cream and Foxtail Millet Dosa (each infused with 1% dry U. fasciata). The functional foods were developed based on trial-and-error method, coupled with sensory panel analysis (semi-trained) to improve the palatability and acceptability. Proximate analysis was performed for all the three food products and fresh U. fasciata thallus, to understand their nutritional composition. The developed products contain a good balanced source of nutrients and rich source of minerals, that could help improve the metabolic process of diabetic patients. The optimized functional foods were lyophilized to convert these products into ready-to-eat commercial recipes. To the best of knowledge, this is the first report on developing functional foods that combines millets and edible seaweeds for their anti-diabetic applications.