Contradictions: How Did Judas Die?  Did Judas Iscariot die by hanging (Matthew 27:5) or did he die by falling and bursting open (Acts 1:18)?  By Dr. Georgia Purdom, AiG–U.S.

The relevant passages are:

Matthew 27:5
Then he threw down the pieces of silver in the temple and departed, and went and hanged himself.

Acts 1:18
Now this man purchased a field with the wages of iniquity; and falling headlong he burst open in the middle and all his entrails gushed out.

Some people have wrongly assumed that Matthew and Luke (the author of Acts) are contradictory in their account of Judas’ death. Since the Bible is inerrant Judas cannot have died by hanging and died by falling and bursting open. Rather they are two different viewpoints of the same event. For example, if I saw a car hit a pedestrian, I might simply say that the pedestrian died because they were hit by the car. The coroner who came on the scene later but did not actually see the accident might give a graphic description of the injuries to the pedestrian. Both the coroner and I are describing the same event just different aspects of it.

Matthew tells us that Judas died by hanging (death is inferred from the passage). Luke, being a doctor, gives us a graphic description of what occurred following the hanging. The reason for ordering the events as such is twofold. First, if someone has fallen and their internal organs spilled out they would die and so could not subsequently die from hanging. Secondly, even when people suffer bad falls they do not usually burst open and have their internal organs spill out. The skin is very tough and even when cut in the abdominal area their internals do not usually spill out. Thus, it is unlikely that Judas could die in this manner merely from falling.

Gruesome as it is, Judas’ dead body hung in the hot sun of Jerusalem, and the bacteria inside his body would have been actively breaking down tissues and cells. A byproduct of bacterial metabolism is often gas. The pressure created by the gas forces fluid out of the cells and tissues and into the body cavities. The body becomes bloated as a result. In addition, tissue decomposition occurs compromising the integrity of the skin. Judas’ body was similar to an overinflated balloon, and as he hit the ground (due to the branch he hung on or the rope itself breaking) the skin easily broke and he burst open with his internal organs spilling out.

There is no contradiction surrounding Judas’ death; rather, merely two descriptions given by two different authors of the same event.
http://www.answersingenesis.org/articles/2009/05/25/contradictions-how-did-judas-die