The majority of the world's rice hectarage is produced in a flooded environment, which greatly impacts the availability of phosphorus (P).  Most soil test extractants were developed for upland crops, and hence may not be reliable in predicting the need for P fertilization.  The Mississippi State University Soil Testing Laboratory utilizes the Lancaster extractant due to its ability to predict P availability over a wide range of soil pH.  The objective of this study was to determine its effectiveness at predicting the need for P-fertilization in dry-seeded, delayed-flooded-rice.  Data collected from P response plots conducted at 13 site-years across 11 locations were used. Soil samples were collected from the untreated plot in each of four replications at each site year.  Whole plant samples were harvested from each plot at panicle differentiation (PD) and panicle emergence (PE).  Finally, grain yields from the untreated plots were standardized across all site years by dividing the untreated yield by the highest yielding treatment in the corresponding replication and multiplied by 100 to produce a percent relative yield (%RY).  Soils were extracted with the Lancaster extractant and analyzed for P (LanP).  Whole plant tissue samples were analyzed for P.  When %RY was related to the linear and quadratic terms of LanP, a non-significant (P=0.40) model with low coefficient of determination (r²=0.08) was obtained; however, a significant model was obtained when the linear and quadratic terms of pH and the LanP x pH interaction term were added to the model that included linear and quadratic terms for LanP and (P=0.032; r² = 0.43).  Similar results were obtained with whole plant P concentrations at PE (P=0.0023; r²=0.58).  Linear LanP and pH terms plus the LanP x pH interaction term produced a significant model (P=0.0009; r²=0.55) when relating whole plant tissue P concentration at PD.  These data indicate that soil test concentrations of P obtained from the Lancaster extractant method do not sufficiently predict the need for P-fertilization alone; however, when soil pH is also considered, the ability for the Lancaster extractant to predict the need for P-fertilization is improved.