Reuters/Ammar Abdullah
Prices were weighed down by a drop in energy prices, particularly a sharp plunge in the gasoline index.
Year-on-year, the basket of consumer prices rose 0.8% (0.9% forecast.)
Excluding the volatile costs of food and energy, so-called core CPI rose 0.1% month-on-month, and 2.2% year-on-year.
Economists had forecast that core inflation rose 0.2% month-on-month, and 2.3% year-on-year.
Core inflation compared to the prior year has been running hot and above the Fed's 2% target since last December. Much of this gain has been due to a jump in shelter costs, which make up 32% of the overall consumer price basket.