We propose a medically driven data mining application: system for diagnosing of gait patterns related to health problems of elderly to support their independent living. Gait of elderly is captured with motion capture system, which consists of tags attached to the body and sensors situated in the apartment. Position of the tags is acquired by the sensors and the resulting time series of position coordinates are analyzed with machine learning algorithms in order to recognize the specific health problem. We propose novel features for training a machine learning classifier that classifies the user's gait into: i) normal, ii) with hemiplegia, iii) with Parkinson's disease, iv) with pain in the back and v) with pain in the leg. Experimental results showed that decision tree classifier was able to reach only 95 % of classification accuracy, using 7 tags and 5 mm standard deviation of noise. On the other hand, k-nearest neighbor was much more accurate since it reached classification accuracy of over 99 %, using only 8 tags with 0-20 mm noise.