Overall consolidated sales rose 19% to $900m (£665m).
Agency commission and fee revenues in the first quarter were up 49%.
Sotheby’s CEO Tad Smith said: “We remain on track to have an even better year in 2018 than we did in 2017.”
Net auction sales were up 46% if including the advantageous impact of a schedule shift for its Hong Kong auctions that were in the second quarter results of the previous year.
Smith said the quarter began well with its annual Masters Week auctions of Old Master paintings, drawings and sculpture in New York, which achieved a total of $82.5m, nearly double the results of the same series of sales the previous year.
Profit in the period, known as net income in the US, reached $5m, up from a loss of $11.4m in the same period a year ago.