diff --git a/index.js b/index.js
index 14e65982..1806526c 100644
--- a/index.js
+++ b/index.js
@@ -1,6 +1,7 @@
 'use strict'
 
 var Ajv = require('ajv')
+var merge = require('deepmerge')
 
 var uglify = null
 var isLong
@@ -86,7 +87,7 @@ function build (schema, options) {
 
   var dependencies = []
   var dependenciesName = []
-  if (hasAnyOf(schema) || hasArrayOfTypes(schema)) {
+  if (hasAnyOf(schema) || hasArrayOfTypes(schema) || hasIf(schema)) {
     dependencies.push(new Ajv())
     dependenciesName.push('ajv')
   }
@@ -143,6 +144,11 @@ function hasArrayOfTypes (schema) {
   return false
 }
 
+function hasIf (schema) {
+  const str = JSON.stringify(schema)
+  return /"if":{/.test(str) && /"then":{/.test(str)
+}
+
 function $asNull () {
   return 'null'
 }
@@ -475,21 +481,15 @@ function buildCode (schema, code, laterCode, name, externalSchema, fullSchema) {
   return { code: code, laterCode: laterCode }
 }
 
-function buildObject (schema, code, name, externalSchema, fullSchema) {
-  code += `
-    function ${name} (obj) {
-      var json = '{'
-      var addComma = false
-  `
-
+function buildInnerObject (schema, name, externalSchema, fullSchema) {
+  var laterCode = ''
+  var code = ''
   if (schema.patternProperties) {
     code += addPatternProperties(schema, externalSchema, fullSchema)
   } else if (schema.additionalProperties && !schema.patternProperties) {
     code += addAdditionalProperties(schema, externalSchema, fullSchema)
   }
 
-  var laterCode = ''
-
   if (schema.allOf) {
     schema.allOf.forEach((ss) => {
       var builtCode = buildCode(ss, code, laterCode, name, externalSchema, fullSchema)
@@ -504,6 +504,60 @@ function buildObject (schema, code, name, externalSchema, fullSchema) {
     laterCode = builtCode.laterCode
   }
 
+  return { code: code, laterCode: laterCode }
+}
+
+function buildObject (schema, code, name, externalSchema, fullSchema) {
+  code += `
+    function ${name} (obj) {
+      var json = '{'
+      var addComma = false
+  `
+
+  var laterCode = ''
+  var r, merged
+  if (schema.if && schema.then) {
+    merged = merge(schema, schema.then)
+    delete merged.if
+    delete merged.then
+    delete merged.else
+
+    code += `
+      var valid = ajv.validate(${require('util').inspect(schema.if, {depth: null})}, obj)
+      if (valid) {
+    `
+
+    r = buildInnerObject(merged, name, externalSchema, fullSchema)
+    code += r.code
+    laterCode = r.laterCode
+
+    code += `
+      }
+    `
+    if (schema.else) {
+      merged = merge(schema, schema.else)
+      delete merged.if
+      delete merged.then
+      delete merged.else
+
+      code += `
+        else {
+      `
+
+      r = buildInnerObject(merged, name, externalSchema, fullSchema)
+      code += r.code
+      laterCode = r.laterCode
+
+      code += `
+        }
+      `
+    }
+  } else {
+    r = buildInnerObject(schema, name, externalSchema, fullSchema)
+    code += r.code
+    laterCode = r.laterCode
+  }
+
   // Removes the comma if is the last element of the string (in case there are not properties)
   code += `
       json += '}'
diff --git a/package.json b/package.json
index d25695e6..be8f5f71 100644
--- a/package.json
+++ b/package.json
@@ -35,6 +35,7 @@
     "uglify-es": "^3.3.10"
   },
   "dependencies": {
-    "ajv": "^6.4.0"
+    "ajv": "^6.4.0",
+    "deepmerge": "^2.1.0"
   }
 }
diff --git a/test/if-then-else.test.js b/test/if-then-else.test.js
new file mode 100644
index 00000000..9ebbabd2
--- /dev/null
+++ b/test/if-then-else.test.js
@@ -0,0 +1,85 @@
+'use strict'
+
+const t = require('tap')
+const build = require('..')
+
+const schema = {
+  'type': 'object',
+  'properties': {
+    'kind': { 'type': 'string', 'enum': ['foobar', 'greeting'] }
+  },
+  'if': {
+    'properties': {
+      'kind': { 'type': 'string', 'enum': ['foobar'] }
+    }
+  },
+  'then': {
+    'properties': {
+      'foo': { 'type': 'string' },
+      'bar': { 'type': 'number' }
+    }
+  },
+  'else': {
+    'properties': {
+      'hi': { 'type': 'string' },
+      'hello': { 'type': 'number' }
+    }
+  }
+}
+
+t.test('if-then-else', t => {
+  const tests = [
+    {
+      name: 'foobar',
+      schema: schema,
+      input: {
+        kind: 'foobar',
+        foo: 'FOO',
+        bar: 42,
+        hi: 'HI',
+        hello: 'HELLO'
+      },
+      expected: JSON.stringify({
+        kind: 'foobar',
+        foo: 'FOO',
+        bar: 42
+      })
+    },
+    {
+      name: 'greeting',
+      schema: schema,
+      input: {
+        kind: 'greeting',
+        foo: 'FOO',
+        bar: 42,
+        hi: 'HI',
+        hello: 45
+      },
+      expected: JSON.stringify({
+        kind: 'greeting',
+        hi: 'HI',
+        hello: 45
+      })
+    }
+  ]
+
+  tests.forEach(test => {
+    t.test(test.name + ' - normal', t => {
+      t.plan(1)
+
+      const stringify = build(test.schema)
+      const serialized = stringify(test.input)
+      t.equal(serialized, test.expected)
+    })
+
+    t.test(test.name + ' - uglify', t => {
+      t.plan(1)
+
+      const stringify = build(test.schema, { uglify: true })
+      const serialized = stringify(test.input)
+      t.equal(serialized, test.expected)
+    })
+  })
+
+  t.end()
+})