Vishnu Sahasranamam or Vishnu Sahasranama Stotram is the most popular prayer dedicated to Lord Vishnu. Here is the link to download Vishnu Sahasranamam in MP3 format. This stotram is popularly chanted on Ekadashi vrat, and other festive days. It describes the 1000 names of Lord Vishnu.
It is believed Vishnu Sahasranama stotram was first chanted by Bhishma and he taught this to Pandavas during Mahabharata war in the Dwapara Yuga. It is mentioned in the Padma Purana.
Download Vishnu Sahasranamam MP3 here in female voice
Download Vishnu Sahasranamam MP3 here in male voice