It is alleged that some of Apple's contractors are withholding royalty payments to the San Diego-based company.
"We have successfully navigated challenges like this in the past, and we have confidence in the sustainability of our licensing business", said Chief Executive Steve Mollenkopf in a conference call with analysts.
Wall Street analysts forecast sales of $5.89 billion and adjusted earnings of $1.22 per share.
Chipset major Qualcomm said its revenue reached $5 billion (-10 percent), while net income was $0.7 billion (-36 percent) for its fiscal second quarter ended March 26, 2017.
The Qualcomm technology licensing (QTL) segment produced $2.25 billion of revenue, up 5% year over year.
The company said its Non-GAAP results do not include the Qualcomm Strategic Initiatives (QSI) segment and certain share-based compensation, acquisition-related items, tax items, and others.
Chip maker Qualcomm might be happy with its recent fiscal performance, but a legal stoush with tech giant Apple might affect its profits for the third quarter of 2017.
Royalties on iPhone sales lately have accounted for about 12% of Qualcomm's total revenue and as much as 30% of its per-share earnings, according to Srini Pajjuri of Macquarie Capital.
Qualcomm's latest smartphone processor, the Snapdragon 835, has gotten good traction in new mobile devices, including the Sony Xperia XZ Premium, the Xiaomi Mi6 and the Samsung Galaxy S8.
Apple's contract manufacturers reported, but underpaid, royalties in Q2'FY17.
Both the chip and licensing businesses performed well during the second quarter, but Qualcomm was forced to provide broad guidance ranges because of its concern that Apple contract manufacturers will continue to underpay royalties.
Qualcomm has separately refused to pay Apple quarterly rebates due to Apple's participation in an antitrust lawsuit against Qualcomm in South Korea, which has led Apple to seek $1 billion in rebate repayments. Apple contends Qualcomm is retaliating for Apple's cooperation with anti-trust regulators. Qualcomm blamed uncertainty over whether this underpayment would continue during the third quarter for its unusually wide guidance range. It predicts sales of $5.3 billion to $6.1 billion, with earnings of 67 cents to 92 cents per share under Generally Accepted Accounting Principles. Apple's alleged interference was retaliation for the chip maker's own withholding of payments it owed to Apple in a separate contract dispute, Qualcomm claimed.
Shares closed at $52.61 Wednesday, down 0.1% for the day.