Discoteca El Son

Great ambience, music and salsa for all levels. There's a variety from salsa, kizumba to bachata so it's all in one place. Different men will come and approach you to dance with you. They are very friendly.
You can also just sit there and become a spectator whilst having drinks on the side.
Toilets are pretty clean when I went.
Ticket is only 10 euros to go inside but it includes a cocktail or beer. Good value for money.

My daughter and I found this little gem on a Thursday night. . . last night of our Spanish holiday; first night in Madrid.  Luckily bumped into a local d.j. at another club who knew we were looking for the best place in Madrid for Latin dance.  He led us right to the door. This place, “el Son”, in the heart of the city did not disappoint. 10 euros cover charge, including a drink was very reasonable. Great atmosphere. Great music, with nice mix of salsa, bachata, merengue and some regaton. We got there at about 10:30 pm.  Fairly quiet with tons of space to move on the dance floor.  Warmed up at midnight with dance floor pretty packed by 12:30 am.  Dancers of all levels having fun. Wish we could have stayed all night but had a morning flight back to U.S. the next day and had to leave just after 1.  Would go back to el Son in a heartbeat and fully recommend to all Salsa (Latin dance) aficionados!

The place is small, and all the seats are reserved, no chance to have a sit.
I came to dance some salsa on Saturday about 11:30pm, and almost no one was there. But, at 1am the place started to be very, very crowded, hundreds of people on a few meters (not sure they don't exceed allowed capacity by fire safety),  none of them even dance, and people continue and continue to come in. I saw maybe 5-6 average+ dancers,  all the others were either beginners or won't dance at all.
Anyway, it doesn't matter, since there wasn't just any space for dancing.
The music is in an annoying cycle of 2 salsa, 2 bachata and 2 kizomba/merengue songs, like if there was a computer and not a DJ.
Anyway, if you are looking for spending the night by a good salsa dancing , you rather search for a better place.

The best Latin DJ discoteque in Madrid without discussion. The best thing in my opinion: "Men are motivated mostly by dance with you but just to dance. I danced with a lot of them and felt like belonging to a club of respectful good dancers. Always observe your drinks.