The Sensex at the Bombay Stock Exchange today gained 165 points, to, 19,869 in late morning deals. This follows buying in frontline shares of oil & gas, health care, realty, consumer durable and teck counters. Earlier, the 30- shre barometer gained 101 points in opening trade.The Nifty at the National Stock Exchange moved up by 42 points, to, 6,028.