Quantitative characterization of the penetration of chemical residues through various types and configurations of clothing is an important underpinning of mitigation strategies to reduce dermal exposure to occupational cohorts. The objective of the evaluation presented herein is the development of pesticide clothing penetration (or conversely protection) factors for single layer clothing (i.e., long-sleeved shirt, long pants; gloves are not included) based on dermal exposure monitoring data (passive dosimetry) included in the Environmental Protection Agency's Pesticide Handlers Exposure Database (PHED). The analysis of penetration per replicate was conducted by comparison of the inside and outside (total deposition), expressed as mug/cm(2), for each replicate pair of dermal dosimeters. Clothing penetration was investigated as a function of job classification, dosimetry sampling method, body part, application method, and type of formulation. Grand mean single layer clothing penetration values for patch (n=2029) and whole-body (n=100) dosimeter samples from PHED were 12.12 (SE=0.33; SD=15.02) and 8.21 (SE=1.01; SD=10.14) percent, respectively. Linear regression was used to evaluate clothing penetration as a function of outer dosimeter loading. The regression analysis supports the hypothesis that single layer clothing penetration increases with decreasing outer dosimeter loading.