Much significance is being attributed to modular instruction curriculums as the importance devoted to environment and environmental education increases gradually. Based on this significance, this paper aims at revealing the effect of designed modular instruction curriculum on “Human and Environment Unit”. To this end, semi-experimental method was used. Sample of the study includes 60 students (7th grade) studying in various classes of a primary school in Gümüşhane. Data collection tool is an achievement test comprised of 50 multiple choice questions. They were prepared considering “Human and Environment Unit”. Independent and dependent t-tests and One-Way ANOVA were used to analyze data. In accordance with the results, it was detected that modular instruction curriculum is more effective than present curriculum due to various reasons: it is a curriculum devoted to environmental education, it has educational attainments regarding environmental education as well as teaching materials, it places emphasis on a sustainable future and finally it attaches importance to socio-scientific and contemporary issues. It is projected that teachers should employ modular instruction curriculum for environ-mental education and the aforementioned curriculum would be more effective in terms of environmental education.