Document and Entity Information - shares
9 Months Ended
Sep. 30, 2019
Oct. 28, 2019
Document And Entity Information [Abstract]    
Document Type 10-Q  
Amendment Flag false  
Document Period End Date Sep. 30, 2019  
Document Fiscal Year Focus 2019  
Document Fiscal Period Focus Q3  
Document Quarterly Report true  
Document Transition Report false  
Entity Registrant Name MercadoLibre, Inc.  
Title of 12(b) Security Common Stock, $0.001 par value per share  
Trading Symbol MELI  
Security Exchange Name NASDAQ  
Entity Central Index Key 0001099590  
Current Fiscal Year End Date --12-31  
Entity Filer Category Large Accelerated Filer  
Entity Incorporation, State or Country Code DE  
Entity Interactive Data Current Yes  
Entity Current Reporting Status Yes  
Entity Small Business false  
Entity Emerging Growth Company false  
Entity Shell Company false  
Entity Common Stock, Shares Outstanding   49,709,955
Entity Address, Address Line One Arias 3751, 7th Floor  
Entity Address, City or Town Buenos Aires  
Entity Address, Postal Zip Code C1430CRG  
Entity Address, Country AR  
Entity File Number 001-33647  
Entity Tax Identification Number 98-0212790  
City Area Code 5411  
Local Phone Number 4640-8000