Despite much promise to overcome drug-resistant infections, clinical studies of bacteriophage anti-bacterial therapy have failed to show durable effectiveness. Although lysogeny plays an important role in bacterial physiology, its significance in diverse microbiomes remains under-studied. Here, we tested the hypotheses that 1) urinary microbiome phage populations switch to a higher relative proportion of temperate phages and 2) the activity of the phage recombination machinery (integration / excision / transposition) is higher during human urinary tract infections (UTIs) than in non-infected urinary tracts. Using human urine, model organisms, mass spectrometry, gene expression analysis, and the phage phenotype prediction model BACPHLIP, the results support our hypotheses at the functional protein and gene level. From a human health perspective, are temperate phages part of the problem and not the defenders we wished them to be? These data support the use of lysogenic phages as a therapeutic Trojan Horses.