The cocaine was found impregnated inside clothes in two checked bags belonging to two women and a man who were subsequently arrested, police said in a statement on Wednesday.
Studies have shown that when the drug is poured onto clothing in the form of cocaine hydrochloride it can account for around 14 percent of the total weight of the garments and keep approximately 89 percent of its purity.
Airport police put the suspicious garments under filtered light to determine if they were indeed soaked in the illicit drug.
They had initially singled out the three passengers, aged 28, 32 and 37, for questioning and searched their luggage after observing that they appeared to be nervous as they waited to pass passport controls.
398 people out of the 45 million passengers that passed through Barajas last year were detained for drug smuggling.
Spain's close ties with its former colonies in Latin America, a major cocaine-producing region, have made the country a key transit point for South American drugs bound for Europe.