Cotton Research Verification Trail fields in Arkansas were sampled during the 1989, 1990 seasons for the prevalence of black root rot on cotton caused the fungus Thielaviopsis basicola. Approximately 45 random seedlings were sampled per field, washed, surface disinfested and plated ont he selective medium TB-CEN (Specht and Griffin, 1985). In addition to frequency of pathogen isolation (disease incidence), the relationship of black root rot to the fields; soil chemical and physical properties and cultural practices were examined. T. basicola was isolated from seedlings in 68% of the 40 fields assayed, with a mean disease incidence of 14%. The percentage of seedlings infected ranged from 0% to 72%. Eight of the 27 fields having infected seedlings had incidence levels greater than 25%. No correlation was found between most soil chemical factors, including soil pH and factors associated with soil H (cation exchange capacity, base saturation and calcium) which have been associated with black root rot (Meyer et al., 1989; Roy and Bourland, 1982), and disease incidence. Among fields, soil pH ranged from 5.3 to 7.2. The only soil chemical factor correlated with black root rot incidence was sodium, which had a correlation coefficient of 0.57 (P=0.001). Sodium concentrations ranged from 100 to 283 lbs/A. for growers reporting cropping history, all fields not cropped to cotton the previous season had no or very low incidence of black root rot, whereas fields cropped to cotton for several years had appreciable black root rot.