There is a dearth of information about how students with visual impairments learn science-process skills. The study presented here investigated students' concepts and skills in one science area: the estimation of measurements. The estimation of measurements is one of the fundamental concepts that connects all science disciplines that provide the necessary skills to understand the natural world (National Research Council, 1996; Roth & Roychoudhury, 1993) and is an instructional goal at every grade level of the Mathematics Standards (National Council of Teachers of Mathematics, 2000). Estimating is as important in the science laboratory as it is in real-world environments. In the laboratory, students are asked to make measurements using tools, such as rulers, balances, and beakers, all of which typically rely on visual perception. Although adaptive technologies are available to a small sample of students, these tools are not universally available for those who need them in mainstream classes (Jones, Taylor, & Broadwell, 2009a). The purpose of this study was to document the reported experiences of students with visual impairments with estimating measurements, as well as the students' conceptualizations of linear distances and accurate estimations.