Google advertising revenue grew 24.4% to $26.6bn, while Google’s other revenues – including hardware and enterprise software – were up 35.8% to $4.4bn.
But rising costs meant the company’s operating margin fell from 27% to 22%.
Speaking on an investor call, Alphabet chief financial officer Ruth Porat said: "The sustained outstanding performance reflects the benefits of innovation and secular growth, with mobile search in particular again leading the way. Robust growth in network revenues was again lead by our programmatic business.
"Ongoing substantial growth in cloud, hardware and Play, continues to highlight the growing contribution of our non-advertising activities."
Discussing YouTube, Google chief executive Sundar Pichai said the company was very focused on making sure YouTube remains a safe platform. We are aggressively combating content that violates our strict policies."
In the fourth quarter of 2017, he said, YouTube had removed more than six million videos for violating policies – and 75% of these had been taken down without receiving a single view.