(FORTUNE Magazine) - At first, unplugging meant going to a hotel that didn't have cable TV. Then came the desire to spend vacations sans cellphone. Now more and more overstressed executives are going a step further: seeking out hotels with no electricity at all. Several such properties are gaining popularity in Mexico, the poshest of which is Hotelito Desconocido on the Pacific Coast. "This is the first place I was really forced to relax," says Shaw McPherson, who works 80 hours a week managing hip L.A. restaurant Ortolan and has visited five times. Desconocido, which was founded by a burnt-out Italian fashion designer, opened in 1999 and, to meet growing demand, was renovated in 2005. Each of the 25 breeze-cooled bungalows (from $302 to $790 a night) is lit with candles, and solar panels power the kitchen and outdoor showers. A lone outlet is outfitted to work only for camera batteries. Elsewhere in Mexico, Eco Paraiso's 15 cabanas (from $141) on the Yucatán Peninsula are embedded in a nature reserve, and the electricity-free Haramara Retreat, on the Pacific Coast, focuses on yoga. The exclusive Small Luxury Hotels of the World counts Desconocido as its only electricity-free member, but spokesman Lanny Grossman predicts more new resorts will follow suit. Says Grossman: "Guests can brag they've done something far more interesting than a typical luxury vacation."