One-third of US workers now have high-deductible health plans, and those numbers are expected to grow in 2014 as implementation of the Affordable Care Act continues. There is concern that high-deductible health plans might cause enrollees of low socioeconomic status to forgo emergency care as a result of burdensome out-of-pocket costs. We analyzed emergency department (ED) visits and hospitalizations over two years among enrollees insured in high-deductible plans through small employers in Massachusetts. We found that plan members of low socioeconomic status experienced 25-30 percent reductions in high-severity ED visits over both years, while hospitalizations declined by 23 percent in year 1 but rose again in year 2. Similar trends were not found among high-deductible plan members of high socioeconomic status. Our findings suggest that plan members of low socioeconomic status at small firms responded inappropriately to high-deductible plans and that initial reductions in high-severity ED visits might have increased the need for subsequent hospitalizations. Policy makers and employers should consider proactive strategies to educate high-deductible plan members about their benefit structures or identify members at higher risk of avoiding needed care. They should also consider implementing means-based deductibles.