I have a problem.

I have a Washing machine that is located in the same room as a toilet. Yesterday when the washing machine drained, the water came out the toilet. does this mean that the Pluming is pluged somewhere between the toilet and the outside world? The house is a older one and I dont know what direction the pipes take in the house. There is only one toilet in the house, so it would make sence if that was the last stop on the way out of the house.