Due to its location near the Atacama desert, the mountain has very dry conditions with snow only remaining on the peak during winter. Despite the generally dry conditions, there is a permanent crater lake about in diameter at an elevation of on the eastern side of Ojos del Salado. This is most likely the highest lake of any kind in the world.
The ascent of Ojos del Salado is mostly a hike except for the final section to the summit which is a difficult scramble that may require ropes. The first ascent was made in 1937 by Jan Alfred Szczepański and Justyn Wojsznis, members of a Polish andinist expedition.
A claim in Andes magazine in 2006 that Ojos del Salado may be higher than Aconcagua, Argentina, was based on older surveys that used inaccurate methods. The results of these older surveys assigned Ojos del Salado an elevation of , which would have made it nearly higher than Aconcagua. In fact, as early as 1955, an estimate was made that the elevation of Ojos del Salado was , but that was "simply an estimate based on the altitude of the final camp, and the hours of ascent to the summit."
In 2007, a Chilean-European expedition performed a precise survey on both Ojos del Salado and Monte Pissis, using more accurate instruments. It found the former to be 6,891 m and the latter 6,793 m. This is slightly lower than recent hand held Global Positioning System (GPS) surveys, which have put it at 6,900–6,905 m (22,630–22,650 ft), though within the vertical error margin of the GPS system.
On Saturday, April 21, 2007, Chileans Gonzalo Bravo G. and his co-driver, Eduardo Canales Moya, claimed to have broken the New High Altitude World Record aboard a vehicle on Ojos del Salado, reaching in altitude, claiming a new Guinness record for Chile, surpassing the mark imposed by a German expedition during the previous March. (The three previous Guinness records were achieved by German expeditions in the same volcano, which, with larger budgets, had set the previous record of .
This record was duly certified by the Guinness World Record on July 2007.
The vehicle used by this expedition was a heavily modified Suzuki SJ (named Suzuki Samurai for the Chilean market) by Bravo. This included: engine swap, axles and suspension modification and important additional equipment such as Air Locker differential , supercharger and a special computer for Air/Fuel modification, among others. The route was planned on the basis of cartography, photographs, satellite images, advice from expert climbers of the volcano, and the routes followed by previous expeditions.
Besides the height and the oxygen shortage, the most significant difficulty in achieving the goal was the variety of terrain, including large rocks, hard sandy slopes, two glaciers, and snowfields. The 800 metre (½ mile) crossing of the main glacier involved "very technical driving", according to Gonzalo Bravo.
The expedition was notable for having only two participants, without support equipment, and with limited resources, as opposed to previous expeditions with used multiple vehicles, up to 19 participants, and up to €500,000.