diff --git a/packages/dd-trace/src/llmobs/sdk.js b/packages/dd-trace/src/llmobs/sdk.js
index 8524e17d37..4a4deda7b7 100644
--- a/packages/dd-trace/src/llmobs/sdk.js
+++ b/packages/dd-trace/src/llmobs/sdk.js
@@ -37,7 +37,7 @@ class LLMObs {
 
     this._handleSpanProcess = data => this._processor.process(data)
 
-    this._enable()
+    if (this.enabled) this._enable()
   }
 
   get enabled () {
diff --git a/packages/dd-trace/test/llmobs/index.spec.js b/packages/dd-trace/test/llmobs/index.spec.js
index e69de29bb2..fd38fb0d9a 100644
--- a/packages/dd-trace/test/llmobs/index.spec.js
+++ b/packages/dd-trace/test/llmobs/index.spec.js
@@ -0,0 +1,68 @@
+'use strict'
+
+const proxyquire = require('proxyquire')
+const { channel } = require('dc-polyfill')
+const injectCh = channel('dd-trace:span:inject')
+
+describe('module', () => {
+  let llmobsModule
+  let store
+  let logger
+
+  beforeEach(() => {
+    store = {}
+    logger = { debug: sinon.stub() }
+    llmobsModule = proxyquire('../../../dd-trace/src/llmobs', {
+      '../log': logger,
+      '../../../datadog-core': {
+        storage: {
+          getStore () {
+            return store
+          }
+        }
+      }
+    })
+  })
+
+  it('injects LLMObs parent ID when there is a parent LLMObs span', () => {
+    llmobsModule.enable({})
+    store.llmobsSpan = {
+      context () {
+        return {
+          toSpanId () {
+            return 'parent-id'
+          }
+        }
+      }
+    }
+
+    const carrier = {
+      'x-datadog-tags': ''
+    }
+    injectCh.publish({ carrier })
+
+    expect(carrier['x-datadog-tags']).to.equal(',_dd.p.llmobs_parent_id=parent-id')
+  })
+
+  it('does not inject LLMObs parent ID when there is no parent LLMObs span', () => {
+    llmobsModule.enable({})
+
+    const carrier = {
+      'x-datadog-tags': ''
+    }
+    injectCh.publish({ carrier })
+    expect(logger.debug).to.have.been.calledWith('No active span to inject LLMObs info.')
+    expect(carrier['x-datadog-tags']).to.equal('')
+  })
+
+  it('does nothing after being disabled', () => {
+    const before = injectCh._subscribers.length
+    llmobsModule.enable({})
+    const during = injectCh._subscribers.length
+    llmobsModule.disable()
+    const after = injectCh._subscribers.length
+
+    expect(during).to.equal(before + 1)
+    expect(after).to.equal(before)
+  })
+})