Yury Shmidt said the appeal - against Khodorkovsky's transfer from Moscow to a prison in the Siberian region of Chita - was sent to a Moscow court on January 10. But when Shmidt arrived at the court Monday to find out the date for the hearing, the appeal was not listed, he said.
The postal service told him that the appeal had been delivered to a court employee, Shmidt said, calling the envelope's disappearance a "circus trick."
The deadline to submit the appeal was January 15, meaning that he and Khodorkovsky had filed the appeal on time, Shmidt said.
Shmidt claims that the Federal Penitentiary Service's decision to send his client to a prison in Siberia's Chita Region was illegal.
Under Russian law the authorities should have imprisoned Khodorkovsky in a region where he either lived or was convicted, the lawyer says.
Khodorkovsky and his business associate Platon Lebedev were initially sentenced to nine years in jail, but had their sentences reduced to eight years after the defense's first appeal in September. Khodorkovsky is serving his sentence in a prison camp in the town of Krasnokamensk, while Lebedev is serving his in the Arctic region of Yamal-Nenets.