Single-phase La4−x−yGd10Ge2B6O34:Ybx,Ery germanate borates have been prepared using liquid-phase homogenization of the starting materials with tartaric acid, followed by annealing at t = 1000 °С and 1200 °C. The samples were characterized by powder XRD, and their morphology (SEM) as well as luminescence with infrared (IR) laser (974 nm) excitation were investigated. All prepared germanate borates crystallize in the trigonal system (sp. gr. P31). Their luminescence spectra contain two groups of bands that correspond to 2H11/2, 4S3/2 → 4I15/2 (green part of the spectrum) and 4F9/2 → 4I15/2 (red part of the spectrum) transitions of the Er3+ ion, with the red band being the more intense. The energy yields of up-conversion luminescence of the synthesized borates were determined. The La2.88Gd10Yb0.7Er0.42Ge2B6O34 and La2.6Gd10Yb0.98Er0.42Ge2B6O34 luminophores with Yb:Er ratios of 5:3 and 7:3 were shown to exhibit the brightest red luminescence.