Abstrak. Tujuan penelitian ini adalah membuktikan bahwa protein pili Shigella dysenteriae  dengan berat molekul 42 kDa merupakan protein adhesi dari S. dysenteriae pada enterosit mencit galur BALB/c. Penelitian ini merupakan penelitian eksperimental laboratoris yang dilaksanakan di Laboratorium Mikrobiologi Fakultas Kedokteran Universitas Jember, melalui beberapa tahap yaitu isolasi dan identifikasi S. dysenteriae, kultur S. dysenteriae, isolasi pili, SDS-PAGE, pemurnian protein pili, uji hemaglutinasi,isolasi enterosit mencit galur BALB/c, dan uji adhesi. Pada penelitian ini dibentuk 6 kelompok perlakuan dan 1 kontrol negatif. Keenam kelompok perlakuan tersebut meliputi konsentrasi protein pili 1, ½, ¼, 1/8, 1/16, dan 1/32. Data dianalisis menggunakan program statistik SPSS (Statistical Product and Service Solution) versi 16, jenis regresi linier sederhana dan one way Anov. Hasil penelitian menunjukkan bahwa protein pili S. dysenteriae 42 kDa mampu menghambat perlekatan S. dysenteriae terhadap enterosit mencit galur BALB/c. Pada uji regresi linier sederhana diperoleh nilai R square 0,897 yang berarti nilai indeks adhesi dipengaruhi oleh konsentrasi protein pili sebesar 89,7%, dan 10,3% dipengaruhi oleh faktor lain. Hasil uji one way Anova menunjukkan bahwa perbedaan konsentrasi protein pili berpengaruh terhadap indeks adhesi bakteri dengan nilai Sig. = 0,000 (p value 0,05). Kesimpulan yang diperoleh dari penelitian ini sesuai dengan hipotesis, yaitu protein pili dengan berat molekul 42 kDa merupakan protein adhesi dari Shigella dysenteriae pada enterosit mencit galur BALB/c. Kata kunci: Shigella dysenteriae,  protein pili  42 kDa, indeks adhesi Abstract. The aim of this study was to prove that the protein pili Shigella dysenteriae with a molecular weight of 42 kDa is an adhesion protein from S. dysenteriae in enterocytes of BALB / c mice. This research is a laboratory experimental research carried out at the Microbiology Laboratory of the Faculty of Medicine, University of Jember, through several stages, namely the isolation and identification of S. dysenteriae, culture of S. dysenteriae, isolation of pili, SDS-PAGE, purification of pili protein, hemagglutination test, isolation of enterocyte strain mice. BALB / c, and adhesion test. In this study, 6 treatment groups and 1 negative control were formed. The six treatment groups included protein concentrations of pili 1, ½, ¼, 1/8, 1/16, and 1/32. The data obtained were analyzed using the statistical program SPSS (Statistical Product and Service Solution) version 16, simple linear regression and one way Anov. The results showed that the 42 kDa S. dysenteriae pili protein was able to inhibit the attachment of S. dysenteriae to enterocytes of the BALB / c mice. In the simple linear regression test, it was obtained that the R square value was 0.897, which means that the adhesion index value was influenced by the pili protein concentration of 89.7%, and 10.3% was influenced by other factors. The one way Anova test results showed that the difference in pili protein concentration had an effect on the bacterial adhesion index with the Sig. = 0.000 (p value 0.05). The conclusion obtained from this study is in accordance with the hypothesis, namely pili protein with a molecular weight of 42 kDa is the adhesion protein of Shigella dysenteriae in enterocytes of BALB / c mice. Key words: Shigella dysenteriae, 42 kDa pili protein, adhesion index