"I Need to Know" is a song recorded by American recording artist Marc Anthony for his eponymous fourth studio album. It was released as the lead single from the album on August 15, 1999. Written and produced by Anthony and Cory Rooney, "I Need to Know" is a song about a man who longs to know how a woman feels about him. The song blends the musical styles of several genres, including R&B and Latin music (genre); the instruments used include violin, piano, timbales and congas. Anthony recorded a Spanish-language version of the song, translated by Angie Chirino and Robert Blades, titled "Dímelo".
Upon its release, "I Need to Know" received mostly positive reviews from music critics and was praised for its production and choice of musical styles. It was nominated for the Grammy Award for Best Male Pop Vocal Performance in 2000. The Spanish-language version of the song won the Latin Grammy Award for Song of the Year in the same year. Both versions of the song won an American Society of Composers, Authors and Publishers award in the pop category. Commercially, the song charted in the top five in Canada and the United States.