Abstract Optofluidic biolasers indicate promising potential and properties that make them highly competitive in the development of state-of-the-art biophotonics technologies. One of the bright outlooks and perspectives that could have a profound impact on the current developing situation and trend of such a new found technology is the photonic crystal based optofluidic biolaser. In this article, we theoretically propose a new lab-on-a-chip design of slotted photonic crystal optofluidic biolaser. Within this scheme, the air slot and medial air holes of the miniaturized photonic crystal slab are infiltrated with organic dye solution, acting as the laser gain region. This structure provides a facility for incorporation of the biological molecules in those fluidic gain mediums. Simulations show that, in addition to the proper lasing characteristics, like the spectral linewidth of 0.27 nm and power conversion efficiency of 26%, the proposed device is highly sensitive to the subtle biological changes that may occur in its cavity and shows the sensitivity of 277 nm/RIU.