ADP said 119,000 jobs were added to the economy in March to April, far short of the 175,000 economists had expected. In addition, it was the first month out of the past five in which private employers added fewer than 200,000 jobs.
ADP said the number was consistent with the gross domestic product's growth rate, which was 2.2 percent on an annualized basis in the first quarter.
By close of trading on Wall Street, the Dow Jones industrial average lost 10.75 points or 0.08 percent, to 13,268.57.
The Nasdaq composite index added 9.41 points, or 0.31 percent, to 3,059.85.
The Standard and Poor's 500 index gave up 3.51 points, or 0.25 percent, to 1,402.31.
On the New York Stock Exchange, 1,326 stocks advanced and 1,700 declined on a volume of 3.8 billion shares traded.
The 10-year treasury note was yielding 1.929 percent.
The euro fell to $1.3152 from Tuesday's $1.3237. Against the yen, the dollar rose to 80.14 yen from Tuesday's 80.09 yen.
In Tokyo, the Nikkei 224 index gained 0.31 percent, 29.30, to 9,380.25.
In London, the FTSE 100 index lost 0.93 percent, 54.12, to 5,758.11.