Elafin is a natural antimicrobial molecule member of the antileukoproteinase (Trappin) family that is normally expressed in the mucosa of human fallopian tubes and neutrophils. Ectopic pregnancy is a condition in which neutrophil influx is present. Current data on elafin expression on fallopian tubes with ectopic pregnancy do not differentiate the expression of elafin in these 2 compartments. The objective of this study was to analyze the protein expression of elafin on epithelial mucosa of fallopian tubes with and without ectopic pregnancy using immunohistochemical analysis. Tissue sections of ectopic pregnancies (n=10) and normal tubes (n=10) were analyzed for the intensity of the staining with 3,3′-diaminobenzidine using ImageJ software. Statistical analysis was performed using unpaired t test and analysis of covariance. Elafin expression (mean±SD) in the mucosa of fallopian tubes was 73.3±19.7 (control) versus 48.9±17.8 (ectopic pregnancy) (P=0.009). The immunoexpression of elafin is reduced in tubal epithelium of ectopic pregnancies, compared with nonectopic pregnancy tubes.