Experimental solubilities of 6-(2,3-dichlorophenyl)-1,2,4-triazine-3,5-diamine (lamotrigine) in binary and ternary solvents of polyethylene glycols (PEGs) 200, 400, and 600 with ethanol and water, and PEGs 200, 400, and 600 with propylene glycol (PG) and water at T=298.2K are reported. The Jouyban-Acree model was used to fit solubility data of lamotrigine in the binary and ternary solvent mixtures (145 data points) in which the overall mean relative deviation (OMRD %) was 11.5%. The density of the solute-free solvent mixtures was measured and employed to calculate the constants of the Jouyban-Acree model and then the density of the saturated solutions is predicted.