Near-infrared (NIR) quantum cutting (QC) through downconversion (DC) in OH− free Nd3+-Yb3+ co-doped low-silica calcium aluminosilicate glasses (LSCAS) was observed. Luminescence and time-resolved measurements allowed the investigation of the origin of the Yb3+ DC emission. Our results showed that only one NIR photon is emitted by the Yb3+ ion through one-step energy transfer after excitation with a VIS photon absorbed by the Nd3+ ion. However, after excitation with an UV photon absorbed by the Nd3+ ion, two NIR photons are emitted by the Yb3+ ion through two-step energy transfer. The Yb3+ DC normalized intensities after excitation at 325 nm showed an increase of a factor of two compared to that of 514 nm excitation. In addition, the energy transfer probabilities from Nd3+ to Yb3+ were estimated by analyzing the Yb3+ DC kinetics. The overall results showed an efficient QC through DC process in Nd3+-Yb3+ co-doped LSCAS glasses, and the energy transfer mechanisms are discussed.