All 26 are accused of evading tests but say there was an administrative error.
The list includes Fabrizio Donato, triple jump bronze medallist at London 2012, and Andrew Howe, who took silver in the long jump at the 2007 World Championships.
They will face trials at the Italian Olympic Committee's anti-doping court, with rulings expected next year.
Five of the 26 athletes have already qualified for next year's Olympic Games in Rio de Janeiro, Brazil.

Ian McCann, head of Rosewood Primary School in Burnley, Lancashire, reportedly took part in a charity bike ride and missed the final week of term.
The 58-year-old handed in a sick note after governors declined his request for absence outside school holidays.
Lancashire County Council topped a recent list of councils fining parents taking children on term-time holidays.
Mr McCann, who could not immediately be reached for comment, will now have to face the school's board of governors.
4,800 Lancashire
3,319 Bradford
2,523 Redbridge
2,402 West Sussex
2,354 Derbyshire
Chairwoman Alex Bird said: "I can confirm that a member of staff has been suspended.
"However, as the matter is subject to investigation we will not be commenting further at this time."
Lancashire County Council issued 3,907 fines to parents for unauthorised absences between September 2014 and July.
Each parent can be fined Â£60, doubling to Â£120 if not paid within 28 days.
Failure to pay can result in court action.
A recent Press Association investigation found the number of fines handed to parents has almost trebled in two years, from 32,512 in 2012-13 to 86,010 in 2014-15.

Japan's shares rose despite a central bank survey showing firms expect inflation to rise 1.4% a year from now, casting doubts on the bank's pledge to hit 2% this fiscal year.
The Nikkei 225 ended up 1.5% at 19,312.79, leading the region's gains.
That is its biggest daily percentage gain since 12 February.
Investors are also awaiting key jobs figures from the US on Friday.
Concerns over the health of the world's largest economy were raised after data on Wednesday showed the pace of US manufacturing growth in March eased to its slowest in nearly two years.
The dollar remained under pressure, buying 119.62 yen.
In China, the Shanghai Composite closed 0.4% higher at 3,825.78, while Hong Kong's Hang Seng index ended up 0.8% at 25,275.64.
In Australia, the S&P/ASX 200 closed up 0.7% at 5,898.6 as bank stocks were boosted on growing expectations of an interest rate cut by the central bank next week.
A private survey also showed that inflation rose from a five-year trough in March as petrol prices rebounded.
The TD Securities-Melbourne Institute's monthly measure of consumer prices rose 0.4% in March, from February when it had been unchanged.
The annual pace was up to 1.5%, from 1.3%, but stayed well below the central bank's target band of 2% to 3%.
The Australian market will be closed on Friday and Monday for the Easter holiday.
South Korean shares closed flat after data showed the country's seasonally-adjusted current account surplus in February at a record high for the second consecutive month.
Exports in February rose by 2% from January while imports fell 0.4%.
The benchmark Kospi index was at 2,029.07.
Italy's Olympic chiefs want 26 of the country's athletes banned for two years over alleged doping offences.
[NEXT_CONCEPT]
A head teacher who went to Brazil on a cycling holiday during term time has been suspended.
[NEXT_CONCEPT]
Asian shares rose on Thursday despite investors being cautious ahead of a Good Friday public holiday in some major markets.