The synthesis and properties of 7-deazapurine β-L-nucleosides are described. The stereoselective glycosylation of the anions of 2-amino-6-chloro-7-deazapurines 9a, 9b or 6-chloro-7-deazapurines 13a, 13d with 3,5-di-O-(4-methylbenzoyl)-2-deoxy-α-L-erythro-pentofuranosyl chloride (8) furnished the β-L-2'-deoxyribonucleosides 1-4. The synthesis of β-L-ribonucleosides 5-7 used the Silyl-Hilbert-Johnson reaction (TMSOTf/BSA/MeCN) performed under Vorbrüggen conditions for the glycosylation of 7-halogenated 6-chloro-2-pivalamido-7-deazapurines 17b-17d with 1-O-acetyl-2,3,5-tri-O-benzoyl-L-ribofuranose (16). Single-crystal X-ray analyses were performed and CD spectra were measured to assign the configuration. The antiviral activity against selected DNA and RNA viruses is reported.