The reported research explored the feasibility of cold bonding as a method to produce low-embodied-energy lightweight aggregates from locally available biomass wastes (wood sawdust and ashes) and cement, using response surface methodology to model the effect of raw material proportions on the properties of the product. The empirical exploration comprised the particle size distribution, saturated surface dry and oven dry density, water absorption capacity, drying shrinkage, short- (7 days) and long-term (70-days) particle crushing strength, and strength variability of the pellets. Aggregates with particle densities below 1.850 g/cm3 and crushing strengths above 1.5 MPa (comparable to expanded clay aggregates) were obtained. In the experimental region explored, increasing sawdust contents to decrease aggregate density negatively affected all the other aggregate properties tested. However, the negative impact was strongly reduced by increasing the ratio of coarse particles in the sawdust. Intermixing cement in the raw material mixture – as opposed to adding it as a coating to the already formed pellets – resulted in better formed, smaller, and stronger pellets, and reduced strength variability. The response model obtained was validated and used to optimize aggregate properties with the specific set of raw materials and production methods studied.