The versatile 28-year-old Italy international completed his medical on Wednesday after agreeing personal terms in advance.
Reports suggest that Juventus paid a fee of just over £1 million for the loan, and would spend £3m to make the deal permanent in the summer if they choose to.
Peluso has three Italy caps and made 116 appearances for Atalanta after joining from Albinoleffe four years ago.
"Obviously it's all really exciting and I'm delighted," he told the club's official website. "I don't think there could be a better way to start off the new year. I'm enjoying the moment and hopefully there will be more good moments to come. "[The last six months] have been, without a doubt, the best of my whole career, and that's what gave me the chance to come to Juventus. "I'm grateful to everyone. It really is a dream come true for me to be here."
Atalanta have been linked with Genoa players Cesare Bovo and Michele Canini as possible replacements.
- Sports & Recreation