A couple lived with the rotting corpse of their seven-year-old son after refusing to believe he was dead, police said.
Bruce and Shrell Hopkins "lost their sense of reality" after their asthmatic son Caleb did not wake up one morning, according to officials.
The exact cause and time of the boy's death is yet to be established but he was last known to be alive on November 15 when he attended a family birthday.
Caleb and his parents, aged 39 and 38, were from Detroit in the US but lived in an apartment in Girona, north eastern Spain.
They were charged with negligent homicide after a judge heard they did not take the child to hospital as they do not believe in standard medicine.
Prosecutor Enrique Barata said Caleb's father told a court they had had previously treated his asthma with inhalers and homeopathic remedies.
Barata added: "One morning the child did not wake up. The father explained he tried to resuscitate his son but he was unresponsive.
"From then on, they lost a sense of reality and would live a normal life around the dead body. They couldn't accept the child was dead."
Police discovered Caleb's body after going to the apartment following a call from the owner who had gone to collect unpaid rent.
Caleb was on a bed at the apartment under several blankets.
Any criminal charges his parents face could be dropped once the post-mortem results come back.