And with that said, I'll turn the call over to Bob.
Robert N. Fisch
Thank you, Stacy. Good afternoon, everyone, and welcome to our fourth quarter and year-end 2011 earnings conference call. I want to spend a few moments giving you an overview of our 2011 results, and then focus on the majority of my comments looking forward to 2012 and our priorities to deliver future growth. Then Kim will give you some insight into our merchandise strategies, and Keith will finish up with the financial results and outlook.
So to start, with a quick look back to the fourth quarter, we were very pleased to have produced net sales growth of approximately 16%, net income growth of almost 19% and earnings per share at $0.52, above our previously stated guidance, despite the warm weather and economic conditions that caused this to be an extremely promotional season for retail. To reiterate what I discussed at the ICR retail conference, from Thanksgiving through the first week of January, we achieved low single-digit comp sales despite industry pressures and unfavorable weather.
We trended up during the biggest volume period of the year by relying on our strong fashion offerings, combined with focused sales on key items to drive the business rather than sacrificing our margins by promoting too aggressively. We did see tough comp sales the last two weekends of January, which was primarily due to unseasonably warm weather across the country, which did rebound in February, which I will be discussing a little later.
The metric we are most proud of this quarter, though, was the 70 basis point increase in merchandise margin during a season when many other retailers experienced significant margin erosion. And certainly, one of the biggest accomplishments in fiscal 2011 was an increased gross margin and merchandise margin in every quarter of the year. We held the line and did not overreact when much of the industry was promoting their entire store.