Learners with dyscalculia in the integrated primary schools in Arusha have been performing poorly in the Primary School Leaving Examination (PSLE). Thus, the journal sought to investigate the impact of instructional resources on mathematics performance of learners with dyscalculia in integrated primary schools found in Arusha city, Tanzania. The main objective of the study were to identify types of instructional resources used by teachers who teach mathematics in integrated schools and to find out the adequacy of instructional resources used to teach Mathematics in integrated schools. The study employed a descriptive design, which was involved with generalized statistics that were abstracted from respondents. The target population was 92 respondents who included head teachers and subject teachers from four schools. A sample size of 52 respondents was obtained through the use of purposive sampling. A questionnaire was used as a major data collection instrument that was administered to head teachers and teachers, and a screening tool checklist complemented it. Data analysis was done manually and computed using Statistical Package for Social Sciences (SPSS). Descriptive statistics was applied to present the findings. The findings revealed that graphic and realia resources to be the most commonly used by teachers. The study also established that all the five main types of instructional resources namely audio, visual, audio-visual, graphic and realia resources were either inadequate or lacking. The study recommends that Government should provide computers and computer software, mathematic kit, radio cassettes and tape recorders which are vital instructional materials in primary schools to enhance effective teaching and learning mathematics. Also, Ministry of Education and Culture should take responsibility in providing instructional resources to schools.