Most of the times you can use them as synonyms. Like if you say: "I go to the bathroom" or "I go to the toilet/loo" (Some people say "baño" is bigger than "aseo" but most of people don't care about it) BTW: Remember they also mean: 1.-Aseo = Cleanliness 2.-Baño = Bathtube I hope that answer helps you :)

Both are synonyms. The real difference is that aseo is when is small and only have the toilet and the sink ; and the baño is bigger and have bathtub or a shower, You can use both but we normally say : Voy al baño.

Hi. To me "aseo" sounds a bit tucky. There is a tiny posibility that spanish people say "Voy al aseo" or "Voy a asearme" because it sounds pretentions and odd. 98% of spanish people will say "Voy al baño". Cheers!

Esta es la otra acepción d ela palabra aseo : Limpieza o arreglo de una persona o una cosa. "el aseo personal; el estuche de aseo despedía un fuerte olor a colonia" Saludos.

They are sinonims. 'Baño' is more used.