A Probabilistic Context Free Grammar (PCFG) for Urdu is developed from a Context Free Grammar (CFG) for sentences and phrases. Probabilities are assigned to the rules with addition of two new terms i.e. special weights and special probability. Weights are assigned to rules after performing certain calculations. Furthermore, if a rule has zero frequency at present but in future it is expected to be used, then instead of assigning zero probability a small value (0.0001 in our case) is assigned to it. All such rules are added like other rules to the Urdu PCFG. An Urdu PCFG is thus obtained.