Studies in reading strategies bring together the assumption that individual characteristics may influence reading performance; different readers may process the same text in different ways, depending on their purposes, motivation, attitudes, interests and background knowledge. The research aims to study the possible relationship between Iranian undergraduate learners' motivation and attitude towards reading comprehension. Therefore, a total number of 285 participants from six different fields of study, social sciences, math, primary education, chemistry, biology and Persian literature took part in this study. The researchers gave the instruments over a 2-day period; the Language Proficiency Test was given on day one, the Motivation for Reading Questionnaire (MRQ), Reading Attitudes Questionnaire (RAQ) and the Reading Comprehension Test on day two with one-week interval. Participants’ responses to the reading motivation and attitude statements, reading comprehension questions, and English language proficiency questions were analyzed through a multiple regression, One-way ANOVA, T-test and correlation. The findings indicated reading motivations and attitudes contribute to better reading comprehension among the subjects. It was also demonstrated that the participants' discipline was a significant contributing factor to the relationship between reading motivation, attitude and reading comprehension ability.