A quantitative method using preadsorbent chemically bonded C₁₈ reversed-phase silica gel plates with fluorescent indicator, automated sample application, and computer-controlled UV absorption densitometry has been developed for the determination of the sunscreen ingredient oxybenzone (OB) in lotions. Nine sunscreen lotions were analyzed to test the proposed method and assess the relationship between OB content and the SPF value stated on the labels. It was found that the amount of OB in the lotions tested ranged from 0.796-6.03% (SPF 4-45). Precision (RSD) was 2.2% for replicate analysis of four sample solutions of one lotion on one plate and 4.6% for four analyses of one sample solution on different plates. Errors from spiked blanks and standard addition analyses to validate accuracy were 0 and 0.67% for the two blanks and 1.3% for the standard addition validation.