Single crystal of Cobalt doped L-Lysine monohydrochloride dihyrate (CLMHCl) was grown by slow evaporation technique from its aqueous solution. The effects of Co-doping on the growth, structural, and optical properties of CLMHCl crystal have been investigated. To grow good quality crystals pH value of growth solution has been optimized and solubility of CLMHCl values was determined. The cell parameters are verified by single crystal X-ray Diffraction. Fourier transform infrared spectum (FT-IR) is used to confirm the presence of various functional groups in the grown crystal. The presence of Co in the grown crystal was confirmed by Inductively-coupled plasma (ICP) elemental analysis. The optical transmission study shows that the CLMHCl crystal has good optical transparency in the UV and visible regions.