If I'm not mistaken, I don't believe any of the Cateye computers...even the high-end ones, have an altitude feature. I too, am interested in this feature...along with temperature, and none of the Cateye's have either. I do know that some of the Sigma computers do have altitude, but that feature doesn't come cheap. I've been seriously looking at the Sigma's...in particular the moderately-priced B1606L DTS + cadence and the much higher-priced ROX 8.0 (which has cadence, HR, altitude, temp and a boatload of other cool features). However, I know next to nothing about Sigma computers...so I have no information on their reliability. I'm currently using a Cateye Strada Wireless, and I've had a few minor interference issues...but other than that, it's been fairly reliable. But I want to move up to a model with cadence and HR, but I'd like the altitude and temp features as well.