The results of a feasibility study to determine if the water sprays produced by residential fire sprinklers can be accurately characterized using phase Doppler interferometry (PDI) are presented. The large size of the water drops produced by fire sprinklers, and the relatively large coverage area of the spray, present significant challenges when attempting to characterize these sprays. These difficulties are especially relevant when using PDI because large drops and large coverage areas may result in trajectory-dependent scattering errors and attenuation of the transmitting laser beams. For the residential sprinkler investigated, it was determined that trajectory ambiguity was nota significant source of error, but attenuation of the laser beam resulted in overcounting of drops due to burst splitting. The effect on the data was minimized by carefully choosing the operating parameters of the PDI processing electronics. For the spray investigated, the Sauter mean diameter varied from approximately 360 to 560 Pm. Integration of the radial profile of the volume flux resulted in a calculated flow rate that agreed with the flow through the sprinkler to with in 8%. The results of this study demonstrate that PDI can be used to accurately characterize the sprays produced by residential fire sprinklers.