This looks like a female false widow (genus Steatoda). Maybe someone who knows more about Mexican Steatoda spiders can guess the species.
Ooog False Widow ... I have Black Widows in my house (though haven't seen any like in years) ... but i know they exists ... so this is a false one hehehe. Thanks!
Spiders ... Spiders everywhere!
I agree, seems to be a female Steatoda grossa ("false widow"). They are pretty widespread in Mexico and South America, especially near the coastlines. We have them along the coasts in North America, too.
This one has some nice, bright markings. They are sometimes more faded or even non-existent (especially in adult females). We have an information page on this species here: http://www.spiders.us/species/steatoda-grossa/.
Actually, it just dawned on me that there are some other species in the 'fulva group' of Steatoda in Mexico that actually have the same markings, so this may not be Steatoda grossa... could be some other species in the same genus.