Phages reconstitute NAD⁺ to counter bacterial immunity. Bacteria defend against phage infection by depleting NAD⁺, a critical molecule for energy and metabolic processes. However, some phages have evolved pathways to reconstitute NAD⁺ from its breakdown products, allowing them to overcome these defenses. Two such pathways, NARP1 and NARP2, were identified. NARP1 involves two enzymes that convert ADPR and nicotinamide into NAD⁺, while NARP2 uses different metabolites. These pathways enable phages to counter multiple NAD⁺-depleting defense systems, including SIR2-HerA, DSR1, DSR2, and SEFIR. Phylogenetic analysis shows that NARP1 is primarily encoded in phage genomes, suggesting a phage-specific function. NARP2, which uses classical NAD⁺-salvage reactions, is also found in phage genomes. These findings reveal a novel immune evasion strategy where phages rebuild molecules depleted by bacterial defenses, thereby overcoming host immunity. The study highlights the importance of NAD⁺ metabolism in bacterial defense against phages and the adaptive strategies phages use to counter these defenses.Phages reconstitute NAD⁺ to counter bacterial immunity. Bacteria defend against phage infection by depleting NAD⁺, a critical molecule for energy and metabolic processes. However, some phages have evolved pathways to reconstitute NAD⁺ from its breakdown products, allowing them to overcome these defenses. Two such pathways, NARP1 and NARP2, were identified. NARP1 involves two enzymes that convert ADPR and nicotinamide into NAD⁺, while NARP2 uses different metabolites. These pathways enable phages to counter multiple NAD⁺-depleting defense systems, including SIR2-HerA, DSR1, DSR2, and SEFIR. Phylogenetic analysis shows that NARP1 is primarily encoded in phage genomes, suggesting a phage-specific function. NARP2, which uses classical NAD⁺-salvage reactions, is also found in phage genomes. These findings reveal a novel immune evasion strategy where phages rebuild molecules depleted by bacterial defenses, thereby overcoming host immunity. The study highlights the importance of NAD⁺ metabolism in bacterial defense against phages and the adaptive strategies phages use to counter these defenses.