This study focuses on the design of a lightweight cement mortar with recycled fine aggregates of wood, plastic, and glass. The normal fine aggregate (sand) was replaced with 20%, 40%, and 60% by weight of sand of recycled aggregates, prepared by cleaning wood sawdust, broken plastic, and broken glass with mechanical milling and then using a mill to obtain a similar gradation to that of the sand. The main goal of this paper was to study the effects of using these recycled aggregates on acoustic and thermal properties as compared with those of the reference cement mortar. Acoustic insulation tests were thus carried out on samples with dimensions of 23 × 23 × 0.8 cm prepared for this purpose at the age of 28 days, with three models for each replacement ratio. The acoustic isolation results showed that cement mortar with sawdust at replacement ratios 20%, 40%, and 60% showed better acoustic isolation properties than cement mortar with plastic and glass with the same replacement percentages or ordinary cement mortar. The thermal insulation of the samples was tested in samples with dimensions of 10 × 5 × 2 cm at 28 days. The results for thermal conductivity coefficients were 0.2353 W.m-1K-1, 0.1981 W.m- 1K-1, and 0.1609 W.m-1K-1 for the replacement ratios 20%, 40%, and 60%, respectively. These results show that the cement mortar with sawdust offered less thermal insulation than cement mortar with plastic debris, while cement mortar with crushed glass was even less thermally isolated.