Coatbridge, Chryston and Bellshill and Airdrie and Shotts followed Motherwell and Wishaw by returning SNP candidates.
Long standing Labour MP Tom Clarke was ousted by Philip Boswell in the former, while Neil Gray grabbed the latter from Pamela Nash.
Mr Clarke had the second largest Labour majority in the country, but a massive swing saw Mr Boswell win by 28,694 votes to 17,195, while Mr Gray took 23,887 votes to Ms Nash’s 15,108.
The other votes in Coatbridge, Chryston and Bellshill were: Mhairi Fraser (Conservative) 3,209; Scott Cairns (UKIP) 1,049 and Robert Simpson (Lib Dem) 549 and in Airdrie and Shotts: Eric Holford (Conservative) 3,389; Matt Williams (UKIP) 1,088; John Love (Lib Dem) and Deryck Beaumont (Independent) 136.
Mr Boswell said: “We insisted on a clean, positive campaign and that buoyed us all the way through, because we believed we were doing something that really mattered.
“The people of Coatbridge, Chryston and Bellshill have spoken, and these are the people I now must serve, it is a massive responsibilty and the hard work starts now.
Mr Gray said: “It’s starting to sink in, I am thrilled and delighted and ready to get to work for the people of Airdrie and Shotts.
“We had to fight a very strong campaign locally to overturn a sizeable Labour majority and we worked tirelessly over the last few months to achieve the victory we did.”