During a recent home game the question of mucking your cards when beat came up. One person said since the other called the bet on the river that person had a right to see the other hand even though the player mucked it. I said that when someone mucks that they admit defeat and no one is allowed to see thier hand unless they flip them up and show them. So does anyone know the actual rule.

PS Since it was my house he didn't have to show

Someone can muck there hand at any point (when it is there turn to act) and it kills their hand and the player forfeits all claims to the pot.

The only time a player has the right to ask to see another players cards is if are suspecting collusion.

Tepshen, most casinos have a rule that if someone calls on the river, anyone can request to see their cards if they muck. As Gnosis said, this is supposed to be used if you suspect collusion, however most people (including dealers and floormen) don't know the reason for the rule, and it gets invoked by players who just want free information and think this rule entitles them to it.

Since it's your home game, go ahead and enforce it properly. If it comes up in a casino, you may be fighting a losing battle if you try to argue it.