A card edge connector includes an elongated housing extending along an elongated direction thereof, and having a first housing half, a second housing half being discrete from the first housing half, and a central slot formed between the first and the second housing halves. A plurality of contacts are retained in the housing, and each has a contact portion protruding into the central slot. A width of the central slot could be adjusted before mounting the card edge connector to a mother board for receiving different daughter boards with different thicknesses.