The infrared spectrum of the transient molecule phosphoryl chloride (ClPO) has been measured in the gas phase at room temperature using infrared diode laser absorption spectroscopy around 8 mu m. The molecule was generated in a flow system either by adding molecular chlorine to a mixture of white phosphorus vapor and oxygen or by reacting atomic oxygen with phosphorus trichloride vapor. The infrared spectrum arises from the P-O stretching fundamental (nu(1)) of ClPO. The band origin is determined as 1263.007 00(22) cm(-1), which is 5 cm(-1) higher than the Ar matrix value and nearly 10 cm(-1) lower than a recent low-resolution gas phase FTIR measurement. The rotational constants derived from the diode laser experiment, A = 1.120, B = 0.151429(29), and C = 0.133 236(23) cm(-1), are very close to those calculated from the density functional theory (B3LYP) structure of RCl-P = 2.0958 Angstrom, RP-O = 1.4650 Angstrom, and angle Cl-P-O = 110.07 degrees.