UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 10-D

ASSET-BACKED ISSUER DISTRIBUTION REPORT PURSUANT TO SECTION 13 OR 15(d) OF

THE SECURITIES EXCHANGE ACT OF 1934

For the monthly distribution period from

April 25, 2006 to May 25, 2006

Commission File Number of issuing entity: 333-130684-01

Morgan Stanley Mortgage Loan Trust 2006-4SL

(Exact name of issuing entity as specified in its charter)

Commission File Number of depositor: 333-130684

Morgan Stanley Capital I Inc.

(Exact name of depositor as specified in its charter)

Morgan Stanley Mortgage Capital Inc.

(Exact name of sponsor as specified in its charter)

New York

(State or other jurisdiction of incorporation or organization of the issuing entity)

Applied for, but not received yet from the I.R.S.

(I.R.S. Employer Identification No.)

	c/o LaSalle Bank National Association 135 South LaSalle Street Chicago, Illinois		60603
	(Address of principal executive offices of the issuing entity)		(Zip Code)

312-904-7323

(Telephone number, including area code)

N/A

(Former name, former address, if changed since last report)

Registered/reporting pursuant to (check one)

				Name of exchange
Title of class	Section 12(b)	Section 12(g)	Section 15(d)	(If Section 12(b))
Classes A-1, M-1, M-2, M-3, B-1, B-2 and B-3	o	o	x	________

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days.

Yes x No o

SEC 2503 (03-05) Potential persons who are to respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB control number.

PART I - DISTRIBUTION INFORMATION

Item 1. Distribution and Pool Performance Information.

The monthly distribution report for the period of April 25, 2006 to May 25, 2006 for the holders of Morgan Stanley Mortgage Loan Trust Mortgage Pass-Through Certificates, Series 2006-4SL is attached as Exhibit 99.1.

PART II - OTHER INFORMATION

Item 2. Legal Proceedings.

None.

Item 3. Sales of Securities and Use of Proceeds.

None.

Item 4. Defaults Upon Senior Securities.

Contained within Item 1, if any.

Item 5. Submission of Matters to a Vote of Security Holders.

None.

Item 6. Significant Obligors of Pool Assets.

None.

Item 7. Significant Enhancement Provider Information.

None.

Item 8. Other Information.

None.

Item 9. Exhibits.

(a) 99.1 Monthly distribution report pursuant to Section 4.04 of the Trust Agreement for the distribution on May 25, 2006.

SIGNATURES*

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned thereunto duly authorized.

		Morgan Stanley Capital I Inc.
Date:	June 1, 2006
		/s/ Steven Shapiro
		Name: Steven Shapiro
		Title: Managing Director

MSM 2006-4SL 10-D