The bodies were found by police and paramedics after they were called to the house on Station Road in Shirebrook at about 22:10 GMT on Friday.
A man has been arrested. He is aged 20 and from Sheffield. He remains in police custody.
Police are investigating the cause of what they say are "suspicious" deaths and have asked anyone with information to contact them.

The study by Napier University found those on benefits were anxious that changes to their circumstances would push them into "crisis situations".
Scottish Social Justice Secretary Alex Neil urged the UK government to rethink its reforms.
But the Department for Work and Pensions said the changes were designed to help people into work.
The Welfare Reform Tracking Study, which was carried out by Edinburgh Napier University on behalf of the Scottish government, also highlighted criticism of how the details of reforms were communicated to recipients of benefits.
Some disabled people who took part in the study said they felt they had to present themselves in a "negative light and focus on their limitations" when claiming.
Other participants spoke of stress, anxiety and depression brought on by assessments, and a fear of further changes.
Mr Neil accused the UK government's "austerity agenda and benefit cuts" of having a "damaging effect" on people in Scotland.
He added: "Their approach is slashing the incomes of some of our poorest households and pushing 100,000 children into poverty.
"The study is further evidence that people are living in constant anxiety about changes to their entitlements and are already suffering from the effects of around Â£6bn of cuts taken from Scottish welfare expenditure over the last five years.
"Despite these frustrations we will do all we can to use our new powers to make our system fairer and simpler and work to improve the experience for people."
However, a spokesman for the Department of Work and pensions said the reforms were about giving people peace of mind.
He added: "Reforms to welfare are designed to help people into work, giving more people the peace of mind and security that comes with a steady income - there are now near record numbers of people in Scotland in a job.
"The government provides a safety net to support millions of people who are unemployed or on low incomes, spending Â£94bn a year across the UK on working age benefits."

A police source told the BBC that an infiltrator from the Taliban had allowed militants into the police station in the regional capital of Lashkar Gah last night.
The infiltrator fled the scene with the Taliban, he said.
A spokesperson for provincial governor Omar Zuak confirmed the incident, but did not provide details.
No group has officially claimed responsibility.
Lashkar Gah has come under increased pressure from the Taliban in recent months.
The city of 200,000 people is seen as strategically important, and the key to holding Helmand province.
The province is both a fertile farming region and a centre for opium production, bordering Pakistan on one end and covering major routes between cities.
Thousands of people fled the rural areas to shelter in Lashkar Gah last August, before the city itself came under attack in October.
The city was previously the scene of heavy fighting between the Taliban and Nato-led forces before their withdrawal in 2014.

Fraudsters posing as TalkTalk workers have switched their caller ID - the incoming number which appears on mobile phone screens - to that of The Flower Shop in Caversham, Reading.
The shop said "confused" callers asking for the telecoms firm had started contacting them on Friday.
The case is being assessed by the National Fraud Intelligence Bureau.
A TalkTalk spokesman said: "We can confirm that this incident is not related to TalkTalk."
Shop manager Denika Potter said some of those ringing the business had been abusive after the fraudsters had tried to dupe them into providing their bank details.
She said many people recognised they were being targeted by scammers, but mistakenly thought the call had originated from the florist.
"Most customers are nice, accept it and apologise," said Ms Potter.
"Some are very annoyed, which you obviously may be if you are getting lots of missed calls from a number."
She said the calls were "disturbing" her staff's daily work and added:  "We are a small business and we're having to stop to answer the phone all the time."
An Action Fraud spokesman said it could take up to 28 days to determine whether there were "sufficient lines of enquiry for an investigation based in the UK".
Two women have been found dead inside a house in Derbyshire.
[NEXT_CONCEPT]
Welfare reforms are making people live in "constant fear" of cuts to their benefits, according to a report.
[NEXT_CONCEPT]
At least 13 policemen were killed by one of their own in Afghanistan's southern Helmand province.
[NEXT_CONCEPT]
A family-run florist says it is being besieged with up to 120 calls a day in a phone cloning scam.