The carrier mobility of discotic lamellar mesophases was evaluated by Time-of-Flight (TOF) method for mesogenic 5,10,15,20-tetrakis(4-n-pentadecylphenyl)porphyrin and was found to be in the order of 10(-4) cm(2) V-1 s(-1). In spite of the higher order of molecular orientation in the lamellar mesophases, it is comparable with that of hexagonal disordered columnar mesophase. This is the first report of charged carrier mobility of a discotic lamellar mesophase.