Labels are the fastest authentication shortcut in vintage clothing. While fabric and construction require hands-on examination, a label can be read in seconds and immediately narrows dating to a specific window.
The Care Label Test (Post-1971)
The single most useful label fact: the US Federal Trade Commission mandated care labels on all garments sold in the US after July 3, 1971. If a garment has a care label with washing instructions, it was manufactured after that date — or had a label added later.
This eliminates a lot of misdating at estate sales. A dress claimed to be "1960s" with a care label stating "Hand wash cold" was either made after 1971 or is an earlier garment with a later label sewn in. Check whether the care label thread matches the construction thread — mismatches indicate later addition.
Union Labels: The ILGWU System
The International Ladies' Garment Workers' Union (ILGWU) label is found on millions of American garments and changes in a dateable sequence:
1900–1920s: Simple text label, "ILGWU" with local number only. 1930s–1940s: Design evolves; oval shape with "ILGWU" text. The specific graphic design of the label changes. 1950s–1960s: The iconic design most collectors recognize — "ILGWU / AFL-CIO" with a distinctive circular logo. The AFL-CIO merger occurred in 1955, so any label reading "AFL-CIO" dates to 1955 or later. 1974: The ILGWU label was updated to include "LOOK FOR THIS LABEL" text. 1995: ILGWU merged with ACWA to form UNITE. Any ILGWU label dates to pre-1995.
The local number also provides geographic information: Local 10 (New York), Local 89 (New York Italian-American), Local 22 (New York), Local 155 (New York). Different locals are associated with specific garment types and price points.
RN Numbers: The Federal Registration System
Registered Number (RN) labels were established in 1952 when the US FTC required manufacturers to register. The number is assigned sequentially — lower numbers indicate earlier registration.
RN numbers below 13144 were issued before 1959. Numbers between 13144 and 38615 were issued 1959–1971. Numbers above 38615 were issued after 1971.
This is a hard floor, not a ceiling: a manufacturer registered in 1965 (RN 15000-range) may have continued using that number on garments made in 1990. But if a garment has an RN below 13000, it cannot have been manufactured before 1952, and the registered manufacturer dates to before 1959.
The RN database is publicly available on the FTC website — you can look up any RN number and find the manufacturer's name and registration date.
Country of Origin: The Import History
Country of origin labels tell a story of global trade that helps with dating:
"Made in USA": Common on pre-1970s garments when American manufacturing was dominant. Still present on some quality American-made garments through the 1980s.
"Made in Japan": Japanese export fashion peaked in the late 1950s–1960s. "Made in Occupied Japan" appears only on items manufactured 1945–1952 during the US occupation.
"Made in Hong Kong": 1950s–1980s. Hong Kong became a major garment manufacturing center after WWII.
"Made in Taiwan": 1960s–1980s, with peak in 1970s.
"Made in Korea": 1970s–1990s.
"Made in China": Broadly from 1980s onward for US imports, though Chinese manufacturing had been restricted by trade law in earlier decades.
"Made in France/Italy/England": Indicates European manufacture; more common in higher-quality and couture garments.
Fiber Content Labels
The Textile Fiber Products Identification Act of 1960 required fiber content labeling on US garments. Before 1960, fiber content is often absent or vague. "All wool," "100% silk" etc. become standard only from the early 1960s.
Before 1960, "Acetate" or "Rayon" might appear, but full percentage breakdowns are absent. A garment claiming to be 1950s with a full fiber content breakdown (e.g., "65% Dacron / 35% Cotton") likely dates to 1960 or later.
The "Made in Occupied Japan" Premium
Any item labeled "Made in Occupied Japan" dates precisely to 1945–1952. This applies to clothing, ceramics, textiles, and accessories. These labels command a collector premium because of their precise datability and historical significance.
Size Labels: The Evolution
Size labeling has changed dramatically. Pre-1960s American sizing ran smaller and was not standardized. A dress labeled "Size 12" from 1955 fits approximately today's size 6–8.
"Petite," "Misses," and "Women's" as formal size categories develop through the 1960s–70s. Before this, sizing was more variable and manufacturer-specific.
Reading Everything Together
A label reading "ILGWU AFL-CIO / Made in USA / Size 10 / 100% Wool" dates to 1955–1971 (AFL-CIO merger through care label law). If the garment also has no care label, we can narrow further to 1955–1971. The fiber content label (100% wool) confirms post-1960.
Cross-reference against construction: does the construction match a 1960–1971 window? Metal zipper (yes, pre-1963 or transitional), shoulder shape, hem length. All three confirming the label range is strong authentication.